United States v. Martin, Troy ( 2010 )


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  •                               In the
    United States Court of Appeals
    For the Seventh Circuit
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    U NITED STATES OF A MERICA,
    Plaintiff-Appellee,
    v.
    T ROY M ARTIN , E DDIE B ELL,
    JOHN B RAYBOY, M ARIO T AYLOR
    and JEROME T ERRELL,
    Defendants-Appellants.
    Appeals from the United States District Court
    for the Northern District of Illinois, Eastern Division.
    No. 1:04-cr-495—Rebecca R. Pallmeyer, Judge.
    A RGUED O CTOBER 7, 2009—D ECIDED A UGUST 24, 2010
    Before R IPPLE, K ANNE and SYKES, Circuit Judges.
    R IPPLE, Circuit Judge. The defendants have been con-
    victed of violating various provisions of 
    21 U.S.C. §§ 841
    ,
    843 and 846, for their respective roles in a narcotics con-
    2           Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    spiracy.1 They have timely appealed their convictions on
    various grounds.2 For the reasons set forth in this opin-
    ion, we affirm the judgment of the district court. How-
    ever, for certain defendants, we order limited remands
    for resentencing.
    I
    BACKGROUND
    On September 7, 2004, a grand jury indicted the defen-
    dants and many other individuals for various narcotics
    and firearm offenses. The indictment described the defen-
    dants’ participation in a sprawling narcotics-distribu-
    tion network on the west side of Chicago, Illinois, that
    had been in existence since 1998. A large part of the
    network consisted of a street gang called the “Mafia
    Insane Vice Lords” or the “Mafia Insanes.” That gang was
    organized hierarchically and employed violence to con-
    trol “drug spots” where narcotics were sold. Individual
    sellers paid a fee to the gang’s leadership (a “street tax”)
    in return for supply of narcotics, protection and the
    ability to sell at the drug spots. Troy Martin was the
    founder and “king” of the Mafia Insanes. Eddie Bell and
    Donnell Simmons were high-ranking members of the
    Mafia Insanes’ leadership who supplied narcotics to the
    1
    The jurisdiction of the district court is based on 
    18 U.S.C. § 3231
    .
    2
    The jurisdiction of this court is based on 
    28 U.S.C. § 1291
    .
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265                3
    sellers and collected street taxes from the drug spots.3
    Jerome Terrell was a member of another gang called
    the “Cicero Insane Vice Lords” and also supplied
    narcotics to Mr. Simmons. Mario Taylor was a member
    of another street gang called the “Four Corner Hustler”
    gang; Mr. Taylor coordinated the supply of narcotics
    to Mr. Simmons and Mr. Terrell. John Braboy assisted
    Mr. Taylor with packaging and transporting narcotics
    to Mr. Simmons.4
    3
    Donnell Simmons’s appeal has been severed from this
    consolidated appeal. References to Mr. Simmons in this opin-
    ion are for contextual purposes only.
    4
    The indictment charged Messrs. Martin, Bell, Simmons,
    Taylor, Braboy and Terrell with conspiracy to possess and
    distribute cocaine in violation of 
    21 U.S.C. § 846
     (“Count One”).
    Mr. Martin also was charged with eighteen counts of using
    a telephone to facilitate a narcotics conspiracy in violation of
    
    21 U.S.C. § 843
    (b). Mr. Bell was charged with one count of
    distributing heroin in violation of 
    21 U.S.C. § 841
    (a)(1) and four
    telephone counts in violation of § 843(b). (The Government
    eventually dismissed the distribution count against Mr. Bell.)
    Mr. Simmons was charged with two distribution counts in
    violation of § 841(a)(1). Mr. Taylor was charged with five
    telephone counts in violation of § 843(b) and five possession
    counts in violation of § 841(a)(1). Mr. Braboy was charged with
    two possession counts in violation of § 841(a)(1). (We note
    that the indictment and the caption of this appeal refer to
    Mr. Braboy as “Brayboy.” However, in his appellate brief, he
    informs us that the proper spelling of his name is “Braboy.” See
    Braboy Appellant’s Br. 2 n.3. Accordingly, we shall refer to him
    (continued...)
    4         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Many of the defendants pleaded guilty. The remaining
    defendants proceeded to trial. In August 2006, Messrs.
    Martin, Bell and two others were tried and convicted. In
    April 2007, Messrs. Taylor and Braboy were tried and
    convicted. In July 2007, Mr. Terrell was tried alone
    and convicted. At each trial, the Government’s evidence
    consisted primarily of wiretap recordings that the Gov-
    ernment had obtained during its investigation into the
    conspiracy, as well as the testimony of police officers,
    federal agents and cooperating witnesses. Additional
    facts shall be provided on an issue-by-issue basis.
    II
    ANALYSIS
    A. Challenge to the Admissibility of the Wiretap Re-
    cordings
    1.
    In December 2002, the Government began utilizing
    the procedures described in Title III of the Omnibus
    Crime Control and Safe Streets Act of 1968, see 
    18 U.S.C. §§ 2510-22
    , for intercepting wire communications of
    suspected members of the conspiracy. Several suspects’
    phones were targeted during the Government’s inves-
    tigation. We are concerned primarily with the Govern-
    4
    (...continued)
    as “Braboy” in this opinion.) Mr. Terrell was charged with
    two distribution/possession counts in violation of § 841(a)(1)
    and three telephone counts in violation of § 843(b).
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265            5
    ment’s wiretaps on the phones of Messrs. Martin and
    Simmons.
    Each time the Government desired to intercept com-
    munications on a particular phone, it sought authoriza-
    tion from the Chief Judge of the United States District
    Court for the Northern District of Illinois. Included with
    the Government’s wiretap applications were probable
    cause affidavits that identified the phone to be targeted
    and a description of the subject matter of the communica-
    tion that the Government expected to intercept. The
    affidavits also described the bases for the Government’s
    belief that criminal matters would be discussed. The
    Chief Judge issued orders authorizing the interception
    of communications on the phones for thirty days at a
    time. If the Government desired to continue a phone
    intercept for longer than thirty days, the Government
    would submit to the Chief Judge a renewal application,
    including updated probable cause affidavits.
    The Government recorded the wiretap intercepts on
    magneto-optical (“MO”) disks. MO disks cannot be edited.
    At the completion of each thirty-day intercept period for
    a particular phone, irrespective of whether the Govern-
    ment had obtained an extension to continue its wire-
    tap on that phone, the Government sealed, in the
    Chief Judge’s presence, the original MO disks.5 The
    Government kept the sealed MO discs in a DEA evidence
    5
    As explained more fully below, the relevant statute in this
    appeal, 
    18 U.S.C. § 2518
    (8)(a), requires the Government to seal
    wiretap intercepts at the completion of each authorized inter-
    cept period.
    6         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    vault. The Government made duplicate recordings of
    each MO disc for its own use in its pending investiga-
    tion. Also, police officers created, in real time, line-sheets
    describing the substance of the intercepted communica-
    tions. These line-sheets were disseminated to officers
    and used extensively in the Government’s pending in-
    vestigation.
    The Government employed these procedures for wire
    communications on the suspects’ phones from approxi-
    mately December 2002 until October 2003. With respect
    to the phones relevant on this appeal, the Chief Judge
    authorized the Government to wiretap Messrs. Martin’s
    and Simmons’s phones for the following periods:
    Mr. Martin’s target phone 2 from February 2003 to Sep-
    tember 9, 2003, and Mr. Simmons’s target phone 4
    from August 2003 to September 17, 2003. See Tr. at 55-58,
    61-62, Mar. 3, 2006.
    In October 2003, the Government’s investigation was
    nearing an end, and the Government planned to arrest
    many of the suspects. The Government intended to
    play the wiretap recordings for the arrestees to
    facilitate the interrogations. However, on October 10,
    2003, the Government discovered that some of its
    working copies of the communications on Messrs.
    Martin’s and Simmons’s phones were incomplete. On
    the same day, the Government informed the Chief Judge
    and sought permission to unseal the MO disks that
    had been stored in the DEA vault. On October 14, 2003,
    the first business day after the Columbus Day holiday,
    the court authorized unsealing. On that same day, the
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265              7
    Government unsealed the recordings in its vault and
    discovered that portions of certain sealed MO discs
    were blank (hereinafter referred to as “the blank-sealed
    recordings”).6 Later, that same day, after receiving
    the Chief Judge’s permission to do so, the Government
    sealed reconstituted MO discs of the blank-sealed re-
    cordings, which the Government had created by dupli-
    cating its working copies; however, certain working
    copies of the blank-sealed recordings had been lost and,
    for those portions of intercepted communications, no
    reconstituted MO discs could be sealed.7
    6
    Specifically, (1) the MO disc purportedly containing re-
    cordings of Mr. Martin’s target phone 2 during the period
    April 16 to May 15, 2003, contained no recordings; (2) the disc
    purportedly containing recordings of Mr. Martin’s target
    phone 2 during the period June 13 to July 11, 2003, contained
    no recordings for the period June 13 to July 8; and (3) the disc
    purportedly containing recordings of Mr. Simmons’s target
    phone 4 during the period August 19 to September 12, 2003,
    contained no recordings of calls between September 9 and
    September 12, and did not include recordings of any calls
    made over the “push-to-talk” feature of the phone. See Appel-
    lee’s Br. 16-17; R.882 at 4-5; see also infra note 17.
    7
    Specifically, on October 14, 2003, the Government sealed
    duplicate recordings of the calls on Mr. Martin’s target phone 2
    for the period June 13 to July 8, and duplicate recordings of the
    calls on Mr. Simmons’s target phone 4 for the period Septem-
    ber 9 to September 12. However, the Government was unable
    to reconstitute the recordings on Mr. Martin’s target phone 2
    (continued...)
    8           Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    The takedown was delayed because of the problem
    with the tapes; the Government continued its investiga-
    tion without using the blank-sealed recordings. For
    instance, the Government developed probable cause
    applications for wiretaps on additional suspects’ phones
    without reference to the contents of the blank-sealed
    recordings. According to one Government agent, the
    Government essentially “set [the blank-sealed re-
    cordings] aside and decided not to use them in any
    further enforcement action or investigation.” Tr. at 61,
    Mar. 3, 2006. Eventually the takedown occurred, and
    Mr. Martin was arrested.
    2.
    During pretrial proceedings, Mr. Martin filed a
    motion to suppress, contending that the Government
    had violated the immediate sealing requirement of 
    18 U.S.C. § 2518
    (8)(a). 8 R.626 at 1. In his view, the statute
    7
    (...continued)
    for the period April 16 to May 15, or recordings of the push-to-
    talk calls on Mr. Simmons’s target phone 4 for the period
    August 19 to September 12. Instead, on October 17, 2003, the
    Government sealed copies of its line-sheets for those periods.
    See Martin/Bell Appellants’ Br. 16-17; R.882 at 4-5.
    8
    That statutory provision reads:
    The contents of any wire, oral, or electronic communica-
    tion intercepted by any means authorized by this
    chapter shall, if possible, be recorded on tape or wire or
    (continued...)
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265                    9
    had been violated because the reconstituted copies had
    not been sealed immediately after the conclusion of
    the wiretaps. He requested an evidentiary hearing “to
    determine whether evidence resulting from the ille-
    gally intercepted conversations should be suppressed.”
    
    Id. at 2
    .
    The Government opposed the motion and Mr. Martin’s
    request for a hearing. R.882. The Government conceded
    that it had sealed MO discs that it believed to have con-
    8
    (...continued)
    other comparable device. The recording of the
    contents of any wire, oral, or electronic communication
    under this subsection shall be done in such a way as
    will protect the recording from editing or other alter-
    ations. Immediately upon the expiration of the period
    of the order, or extensions thereof, such recordings
    shall be made available to the judge issuing such
    order and sealed under his directions. Custody of the
    recordings shall be wherever the judge orders. They
    shall not be destroyed except upon an order of the
    issuing or denying judge and in any event shall be
    kept for ten years. Duplicate recordings may be
    made for use or disclosure pursuant to the provisions
    of subsections (1) and (2) of section 2517 of this chapter
    for investigations. The presence of the seal provided
    for by this subsection, or a satisfactory explanation
    for the absence thereof, shall be a prerequisite for
    the use or disclosure of the contents of any wire, oral, or
    electronic communication or evidence derived there-
    from under subsection (3) of section 2517.
    
    18 U.S.C. § 2518
    (8)(a).
    10         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    tained recordings, but which were actually blank or
    partially blank. 
    Id. at 1
    . However, the Government vol-
    unteered not to use any of the blank-sealed recordings
    as evidence at trial. 
    Id. at 7
    . With respect to evidence
    derived from those recordings, the Government con-
    tended that the derivative evidence should be admissible
    for two reasons. First, the Government contended
    that, even though it would not use the blank-sealed
    recordings at trial, they were admissible in any event
    because the Government had a “satisfactory explanation”
    for the non-sealing: “DEA technician error.” 
    Id. at 9-10
    .9
    9
    The Government included an affidavit from Victor Jasevicius,
    Group Supervisor for the DEA Technical Operations Group
    that conducted the wiretaps, which stated,
    After the DEA learned in mid-October 2003 that some
    previously-sealed MO discs did not contain any or
    complete call data for certain wiretap interception
    periods, DEA conducted an investigation into the
    particular reason why the equipment used to intercept
    and record communications would produce a blank
    or incomplete MO disc. DEA concluded that a number
    of operator errors could have occurred, including the
    failure to properly input or activate a job order, as
    required by the program, or the assignment of a job
    to the incorrect MO disc. Any one of those errors
    could have been the cause, but no final determination
    could be made because the computer system’s log
    did not reflect which of the possible errors occurred.
    [ ] Tests performed on the equipment determined that
    it was functioning within its design specifications.
    DEA determined that the same operator was involved
    (continued...)
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265               11
    Second, the Government contended that evidence
    derived from the blank-sealed recordings, before the
    sealing obligation arose for those recordings, should be admis-
    sible because 
    18 U.S.C. § 2517
    (1)-(2) permits the use of
    recordings for investigatory purposes. 
    Id.
     at 11-12 (citing
    United States v. Donlan, 
    825 F.2d 653
    , 657 (2d Cir. 1987)).
    Confronting the prohibition in § 2518(8)(a) against the
    use or disclosure at trial of evidence derived from
    unsealed recordings, the Government contended that
    the prohibition should not be applied strictly. The Gov-
    ernment urged the district court to adopt the United
    States Court of Appeals for the Second Circuit’s broad
    construction of the statute, as explained in United States
    v. Donlan, 
    825 F.2d 653
     (2d Cir. 1987).
    In response, Mr. Martin contended that no excuse could
    justify the major delay in sealing that had occurred in
    his case. R.927. He refuted the Government’s proposed
    excuse—operator error—as unsupported by the record
    because the Jasevicius affidavit stated that the DEA “was
    unable to conclude why the error occurred.” Id. at 3.
    Furthermore, Mr. Martin contended that the Supreme
    9
    (...continued)
    in the job orders creating those MO discs which were
    found to be partially or completely blank. DEA has re-
    assigned this technician to other responsibilities and
    taken other steps to ensure that the problem does not
    recur. Following the change in technicians, DEA has
    not experienced any similar problems.
    R.882, Ex. 7, ¶¶ 5-6.
    12       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Court of the United States has not endorsed “mistaken
    belief” as a satisfactory explanation for a sealing error.
    Id. at 3-4 (citing United States v. Ojeda Rios, 
    495 U.S. 257
    (1990)). Nor was lack of proof of alteration sufficient
    to excuse the sealing error because, according to the
    Supreme Court, “ ‘[t]o hold that proof of nontampering
    is a substitute for a satisfactory explanation is foreclosed
    by the plain words of the sealing provision.’ ” Id. at 3
    (quoting Ojeda Rios, 
    495 U.S. at 264
    ). Finally, Mr. Martin
    contended that no derivative evidence should be
    admitted because Donlan and its broad construction of
    § 2518(8)(a) misunderstood “the context of the entire
    statute.” Id. at 4.
    The district court held an evidentiary hearing on the
    motion to suppress. The district court stated that, because
    the Government had volunteered not to use the actual
    tapes, the district court understood Mr. Martin’s motion
    only to apply to “any information that’s derivative of
    the tapes.” Tr. at 3, Feb. 17, 2006. The district court
    wanted to know “exactly what information we are
    talking about.” Id. In response, the Government explained
    that it had planned to use the blank-sealed recordings
    in draft affidavits and complaints to secure arrest war-
    rants in October 2003. Id. at 11-12. Then, when the
    sealing problem was discovered in mid-October, the
    Government scrapped those drafts and decided simply
    to exclude the problematic calls from its investigation
    from that point forward. Id. However, the Government
    conceded that it had used information obtained from
    the blank-sealed recordings in order to prepare officers
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265       13
    while the wiretaps were still active—i.e., during the
    investigation. Id. at 11. The Government raised its two ar-
    guments for why the derivative evidence—any derivative
    evidence—was admissible: the satisfactory excuse for
    non-sealing and the broad interpretation of § 2518(8)(a).
    At the evidentiary hearing, Mr. Martin contended that
    the Government had the burden to show what evidence
    was derived from the blank-sealed recordings. Id. at 14,
    22, 36, 39. He contended that the Government had failed
    to meet its burden, but, in any event, he posited that the
    derivative evidence was extensive because “during each
    one of these tapings [the Government] ha[d] agents
    monitoring these calls,” “making line sheets and making
    summaries of the calls,” and “making transcripts of the
    calls.” Id. at 14; see also id. at 37. Mr. Martin contended
    that the line-sheets, summaries and transcripts were
    used throughout the Government’s investigation, which
    “mushroom[ed] out from the wiretaps.” Id. at 14-16; see
    also id. at 20 (“There is no way we can now go back and
    sort out and say, ‘Well, they didn’t use that[,] . . . they
    erased the knowledge that they obtained.’ ”). Mr. Martin
    suggested that if the Government could not establish
    what derivative use was made of the blank-sealed re-
    cordings, the proper sanction would be to dismiss the
    indictment. Id. at 21-22. He also reiterated his opposition
    to the Government’s two arguments for the admissi-
    bility of the derivative evidence.
    The district court suggested that this case was sui
    generis because the Government made a mistake in
    recording, not in sealing. Id. at 30-31. The district court
    14       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    stated, “I am really uncomfortable with the idea that we
    ought to somehow say that everything during the taped
    period is off the—is somehow tainted in a way that re-
    quires dismissal of the indictment . . . . It seems to be a
    sledgehammer of relief when what we really need is
    much more of a precision tool.” Id. at 33. Instead, the
    district court requested more information about how the
    Government had used its copies of the blank-sealed
    recordings and clarification on what exactly was
    derived from them. Id. at 34.
    Another hearing was held, and Mr. Martin cross-exam-
    ined DEA special agent Jeffrey Konvalinka, who had
    managed the investigation and the wiretap operation.
    Mr. Martin’s counsel asked Agent Konvalinka about
    when and how the blank-sealed recordings were used.
    See generally Tr. at 70, Mar. 3, 2006 (describing how sum-
    maries and line-sheets were prepared as calls were re-
    corded); id. at 71-72, 74-75 (describing how information
    derived from the blank-sealed calls was routed to
    officers to assist their surveillance efforts). Mr. Martin
    argued to the district court that the Government used
    the blank-sealed recordings to secure additional wiretap
    authorizations and, thus, that the sealing problem was
    so pervasive that the indictment must be dismissed.
    See id. at 104.
    The district court declined to rule, despite the Govern-
    ment’s request that the court do so, on the Govern-
    ment’s first argument for admissibility: that the Govern-
    ment had a satisfactory explanation for the sealing error.
    The district court considered that issue to be “moot,”
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265                   15
    because the court found that the blank-sealed recordings
    “were not used in connection with any ongoing ar-
    rests,” “weren’t presented to the grand jury,” “weren’t
    used in any affidavits for purposes of search warrants,”
    “weren’t used to draft any complaints,” and “weren’t
    used in connection with obtaining an indictment.” Id. at
    99, 101. The district court stated, “I haven’t heard about
    what specific improper use of any of this evidence has
    happened.” Id. at 100. Nevertheless, the district court
    seems to have concluded that at least some evidence
    was derived from the blank-sealed recordings. 1 0 The
    district court noted that the Government stopped using
    the blank-sealed recordings as soon as the sealing error
    was discovered and did not intend to use them as evi-
    10
    Later in its ruling, the district court stated that “it is theoreti-
    cally possible that some information that shows up in the
    line records or in the transcripts was in the minds of agents
    when they went out and did their further investigation,” Tr.
    at 99, Mar. 3, 2006, and the district court recognized that the
    blank-sealed recordings had been included in the Govern-
    ment’s probable cause affidavits to obtain additional wiretap
    authorizations, id. at 104. With respect to this derivative evi-
    dence, the district court appears to have agreed with the Gov-
    ernment’s theory that § 2518 should be applied broadly,
    as articulated by the United States Court of Appeals for the
    Second Circuit in United States v. Donlan, 
    825 F.2d 653
     (2d Cir.
    1987). In other words, the district court believed that § 2518
    permitted use at trial of evidence derived from wiretap re-
    cordings, as long as the derivation occurred prior to the vio-
    lation of the wiretap’s sealing obligation. Id. at 100, 104-05.
    16        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    dence at trial. Thus, the district court ruled that “the
    motion is effectively granted without objection.” Id. at 99.
    Mr. Martin proceeded to trial, during which 160 incrimi-
    nating recordings of calls from the wiretapped phones
    and transcripts of the calls were admitted into evidence.
    See generally Trial Tr. at 85-86, 95-96, 103, 107, Aug. 30, 2006.
    Neither the blank-sealed recordings nor any transcripts
    of those recordings were admitted. Mr. Martin was con-
    victed and sentenced to life in prison.
    Mr. Martin appealed his conviction to this court, con-
    tending that the district court had erred by refusing to
    dismiss the indictment.1 1 After hearing oral arguments
    and considering the parties’ submissions, we maintained
    jurisdiction over the case and granted a limited remand
    to the district court to rule on whether the Government
    had a satisfactory explanation for the sealing error, the
    issue it had pretermitted earlier. See App. R.112 (No. 07-
    2272).
    The district court considered the issue and ruled that
    “the government’s explanation for its failure to seal is
    satisfactory.” R.2374 at 3. The district court noted that
    11
    Although the district court’s ruling was characterized in terms
    of granting Mr. Martin’s motion to suppress, the district court’s
    March 3, 2006 ruling properly is understood as constituting
    a denial of the motion with respect to both the evidence
    derived from the blank-sealed recordings and Mr. Martin’s
    request to dismiss the indictment. All parties have proceeded
    under that assumption.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265       17
    the Government never has stated definitively the cause
    for the sealing error, but believed it was caused by
    operator error. The district court applied the framework
    articulated in United States v. Coney, 
    407 F.3d 871
    , 875
    (7th Cir. 2005), and concluded that the Government’s
    explanation was satisfactory. The district court noted
    that the Government’s explanation was believable be-
    cause all of the Government’s actions had been consistent
    with its reasonable belief that it had, in fact, properly
    sealed the blank-sealed recordings. The district court
    did not find the length of delay in sealing to be “trouble-
    some.” Id. at 4. The district court believed the nature
    of the crime charged and the relative lack of notoriety
    of the defendants tended to support the Government’s
    explanation because nothing about this narcotics conspir-
    acy case was unusual. Finally, the district court con-
    sidered the importance of the problematic recordings to
    be minimal because the Government did not use them
    once it realized that the sealing error had occurred
    and because they played no part during the trial.
    3.
    The parties’ contentions before this court largely
    mirror the arguments made during the district court
    proceedings. Mr. Martin contends that the district court
    misapplied § 2518(8)(a). He contends that the district
    court should have found that the Government lacked
    a satisfactory explanation for the sealing error. He fur-
    ther contends that so much evidence was derived from
    the blank-sealed recordings that, without a satisfactory
    18       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    explanation for the sealing error, much of the Govern-
    ment’s evidence at trial should have been excluded.
    He asks that his conviction be reversed.
    The Government concedes that the reconstituted re-
    cordings were not tendered for judicial sealing immedi-
    ately upon the expiration of the wiretap authorizations.
    The Government urges us to interpret § 2518(8)(a)
    broadly so as not to require suppression of the derivative
    evidence. Alternatively, the Government contends that
    the operator error and the Government’s good-faith
    attempt to comply with the sealing requirement con-
    stitute satisfactory explanations for its failure to comply
    with the sealing statute.
    4.
    Title III of the Omnibus Crime Control and Safe Streets
    Act of 1968 established a comprehensive statutory regime
    by which the Government may intercept wire, oral or
    electronic communications. See 
    18 U.S.C. §§ 2510-22
    ;
    Clifford S. Fishman & Anne T. McKenna, Wiretapping
    and Eavesdropping: Surveillance in the Internet Age § 1:10
    (3d ed. 2009) (providing background); Wayne R. LaFave
    et al., Criminal Procedure §§ 4.5-4.6 (5th ed. 2009) (dis-
    cussing the history of the Act and its amendments). The
    Act created procedural safeguards to protect individuals’
    privacy and to prevent other forms of misuse of wire-
    tapping. See generally 
    18 U.S.C. § 2518
     (establishing wire-
    tap authorization procedures for the Government). One
    of the safeguards of this statute is a provision where-
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265               19
    by wiretap intercepts may be authorized only for thirty
    days at a time; any extension must comply with the
    same procedures required to obtain an initial wiretap
    authorization. See 
    18 U.S.C. § 2518
    (5).1 2 The Act also
    strictly regulates how intercepted communication may
    be used or disclosed during and subsequent to a Govern-
    ment investigation. See generally 
    18 U.S.C. § 2517
    .
    The Act requires that wiretap intercepts “shall, if possi-
    ble, be recorded . . . in such a way as will protect the
    recording from editing or other alterations.” 
    18 U.S.C. § 2518
    (8)(a). “Immediately upon the expiration of the
    period of the [wiretap authorization] order, or extension
    thereof, such recordings shall be made available to the
    judge issuing such order and sealed under his direc-
    tions.” 
    Id.
     The purpose of this sealing requirement “is to
    ensure the reliability and integrity of evidence obtained
    by means of electronic surveillance.” United States v. Ojeda
    Rios, 
    495 U.S. 257
    , 263 (1990). “[T]he seal is a means of
    ensuring that subsequent to its placement on a tape, the
    Government has no opportunity to tamper with, alter, or
    edit the conversations that have been recorded.” 
    Id.
     We
    apply the immediacy requirement strictly. See United
    12
    “ ‘[A]n order authorizing surveillance of the same subject, at
    the same location, regarding the same matter as an earlier
    authorized surveillance, constitutes an “extension” of the
    earlier authorization . . . .’ ” United States v. Jackson, 
    207 F.3d 910
    , 916 (7th Cir. 2000) (quoting United States v. Carson, 
    969 F.2d 1480
    , 1488 (3d Cir. 1992)), judgment vacated on other
    grounds, 
    531 U.S. 953
     (2000).
    20       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    States v. Coney, 
    407 F.3d 871
    , 873 (7th Cir. 2005) (“ ‘The
    term “[i]mmediately” means that the tapes should be
    sealed either as soon as practical after the surveillance
    ends or as soon as practical after the final extension
    order expires.’ ” (quoting United States v. Williams, 
    124 F.3d 411
    , 429 (3d Cir. 1997))); see also Fishman & McKenna,
    supra, § 19:10 (discussing other circuits’ application of the
    immediacy requirement). The Supreme Court also has
    stated that Ҥ 2518(8)(a) applies to a delay in sealing, as
    well as to a complete failure to seal, tapes.” Ojeda Rios,
    
    495 U.S. at 264
    . Similarly, we believe that what occurred
    in this case, sealing blank recordings, does not comply
    with the sealing requirement. Cf. 
    id. at 263
     (“The presence
    or absence of a seal does not in itself establish the
    integrity of electronic surveillance tapes. Rather, the seal
    is a means of ensuring that subsequent to its placement
    on a tape, the Government has no opportunity to tamper
    with, alter, or edit the conversations that have been
    recorded.”). Nor is the sealing of line-sheets or call sum-
    maries a proper method of compliance.
    The sealing provision includes its own exclusionary
    remedy: “The presence of the seal provided for by this
    subsection, or a satisfactory explanation for the absence
    thereof, shall be a prerequisite for the use or disclosure
    of the contents of any wire, oral, or electronic communi-
    cation or evidence derived therefrom under subsec-
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265              21
    tion (3) of section 2517.” 1 3 
    18 U.S.C. § 2518
    (8)(a).1 4
    The Supreme Court has noted that the satisfactory
    explanation prong of § 2518(8)(a) “require[s] that the
    13
    Subsection (3) of § 2517 provides:
    Any person who has received, by any means authorized
    by this chapter, any information concerning a wire,
    oral, or electronic communication, or evidence
    derived therefrom intercepted in accordance with the
    provisions of this chapter may disclose the contents
    of that communication or such derivative evidence
    while giving testimony under oath or affirmation in
    any proceeding held under the authority of the
    United States or of any State or political subdivision
    thereof.
    14
    The United States Court of Appeals for the Second Circuit
    has articulated an interpretation of the § 2518(8)(a) exclu-
    sionary remedy that would permit certain uses of wiretap
    recordings, despite the lack of a satisfactory explanation for a
    violation of the statute’s immediate sealing requirement. See
    United States v. Donlan, 
    825 F.2d 653
     (2d Cir. 1987). As best we
    can tell, this interpretation has not been adopted by any other
    court of appeals. See Clifford S. Fishman & Anne T. McKenna,
    Wiretapping and Eavesdropping: Surveillance in the Internet Age
    § 19:8 (3d ed. 2009) (suggesting that courts have divided over
    the correctness of the Donlan interpretation). Although the
    parties differ over the correctness of Donlan, and therefore
    the propriety of the district court’s application of Donlan’s
    rationale, see supra note 10, resolution of this issue is unneces-
    sary. The Government has provided a satisfactory explanation
    for its sealing error, and our discussion will be limited to that
    aspect of the statutory provision.
    22         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Government explain not only why a delay occurred but
    also why it is excusable.” Ojeda Rios, 
    495 U.S. at 265
    . In
    Ojeda Rios, the Supreme Court concluded that the Gov-
    ernment’s “good-faith, objectively reasonable misunder-
    standing of the statutory term ‘extension’ ” was a satisfac-
    tory explanation for the Government’s failure to seal
    immediately wiretap recordings. 
    Id. at 264-66
    .1 5 The
    Supreme Court insisted on a showing of “good cause
    for the sealing delays” and rejected the Government’s
    attempt to show merely that no tampering with the
    15
    However, the Court remanded the case so that the district
    court could determine whether the Government’s proffered
    explanation was supported by the factual record developed
    before the district court. Courts of Appeals similarly have
    reviewed this issue on the basis of an evidentiary record.
    See, e.g., United States v. Wilkinson, 
    53 F.3d 757
    , 759-60 (6th Cir.
    1995) (considering the Government’s explanation for delayed
    sealing as articulated during a “lengthy evidentiary hearing”);
    see also United States v. Ojeda Rios, 
    495 U.S. 257
    , 267-68 (1990)
    (O’Connor, J., concurring) (“[A] ‘satisfactory explanation’ . . .
    cannot merely be a reasonable excuse for the delay; it must
    also reflect the actual reason for the delay” and “should be
    based on the findings made and evidence presented in the
    district court, rather than on a post hoc explanation given for
    the first time on appeal.”). But see Jackson, 
    207 F.3d at 918
    (examining a Government’s proffered explanation that was
    unsupported by evidence submitted to the district court);
    United States v. Hoover, 
    246 F.3d 1054
    , 1063-65 (7th Cir. 2001)
    (Rovner, J., concurring) (criticizing Jackson’s reliance on argu-
    ments not included in the evidentiary record). In this case,
    we rely solely on arguments supported by the factual record
    developed in the district court.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         23
    recordings had occurred. Id. at 264-65 (“To hold that
    proof of nontampering is a substitute for a satisfactory
    explanation is foreclosed by the plain words of the
    sealing provision.”). We have noted that “what should
    be deemed ‘satisfactory’ in the context of a statute
    aimed at preventing government tampering with elec-
    tronic evidence” must depend largely on “the statutory
    objective.” Coney, 
    407 F.3d at 875
    . A satisfactory explana-
    tion must dispel any reasonable suspicion of tampering,
    and also must be both accurate and believable. 
    Id.
    Whether the explanation is satisfactory also may depend
    on the delay in sealing, unique pressure on the Govern-
    ment to obtain a conviction due to particularly notorious
    charges or defendants, the importance of the recordings
    to the Government’s case and whether the Government
    has established a procedure for complying with its
    sealing obligations. Id.; cf. United States v. Mora, 
    821 F.2d 860
    , 867-69 (1st Cir. 1987) (listing additional factors that
    the court believed contributed to satisfactoriness but
    stressing “that there is no stock formula by which the
    adequacy of an explanation can invariably be gauged”).
    In Coney, we applied these principles and held that
    “mixed-signals” between Assistant United States Attor-
    neys qualified as a satisfactory explanation for a ten-day
    delay in sealing. Coney, 
    407 F.3d at 875
    . In other cases,
    we have concluded that a prosecutor’s mistaken belief,
    caused by recording technicians’ delay, about the time
    needed to secure a replacement recording device con-
    stituted a satisfactory explanation, see United States v.
    Jackson, 
    207 F.3d 910
    , 918 (7th Cir.), judgment vacated on
    other grounds, 
    531 U.S. 953
     (2000), as did a bureaucratically
    24        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    caused delay, see United States v. Plescia, 
    48 F.3d 1452
    ,
    1463 (7th Cir. 1995).
    We review for clear error a district court’s conclusion
    that the Government’s explanation for failing to seal
    immediately wiretap recordings is satisfactory. See Coney,
    
    407 F.3d at 874
    .16
    5.
    We begin by noting that evidence was derived from the
    blank-sealed recordings. Although the district court
    did not specify the extent of the derivative evidence,
    it stated that “it is theoretically possible that some infor-
    mation that shows up in the line records or in the tran-
    scripts was in the minds of agents when they went out
    and did their further investigation,” Tr. at 99, Mar. 3,
    2006, and the district court recognized that the blank-
    sealed recordings had been included in the Govern-
    ment’s probable cause affidavits to obtain additional
    wiretap authorizations, id. at 104; see also supra note 10.
    We also believe the factual record would support a
    finding that at least some derivative evidence existed.
    16
    In United States v. Coney, 
    407 F.3d 871
     (7th Cir. 2005), we
    employed the “clearly erroneous” standard while conceding
    that other circuits review this determination de novo. See, e.g.,
    United States v. Reed, 
    575 F.3d 900
    , 913 (9th Cir. 2009);
    United States v. Cline, 
    349 F.3d 1276
    , 1284 (10th Cir. 2003);
    United States v. Sawyers, 
    963 F.2d 157
    , 159 (8th Cir. 1992);
    United States v. Maldonado-Rivera, 
    922 F.2d 934
    , 949-50 (2d Cir.
    1990). But see Wilkinson, 
    53 F.3d at 759-60
    . In this case, we
    would reach the same result under either standard.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265          25
    Our review of the record reveals that portions of the
    Government’s investigation relied on, at least in part, the
    contents of the blank-sealed recordings. For example,
    excerpts of probable cause affidavits show that the Gov-
    ernment frequently cited the communication heard on
    the blank-sealed recordings to secure subsequent wire-
    tap authorizations. See, e.g., R.882-7 at 425; R.882-8 at 253,
    255-56, 293; R.882-9 at 341-42. Also, Agent Konvalinka
    testified that the contents of the blank-sealed recordings
    were relayed to other officers to assist with the
    pending investigation. Because the Government volun-
    tarily suppressed the blank-sealed recordings them-
    selves, the derivative evidence properly was the subject
    of Mr. Martin’s motion to suppress.
    As we have noted earlier, the district court, applying
    the factors set forth in Coney, concluded that the deriva-
    tive evidence need not be excluded because the Gov-
    ernment provided a satisfactory explanation for its im-
    proper sealing. We agree. The record establishes that
    operator error most likely caused the blank-sealed re-
    cordings to be defective. The district court placed this
    error in the proper context. The error had more to do
    with the mechanics of the recording process than
    with the Government’s established sealing procedures.
    Throughout the course of its investigation, the Govern-
    ment acted consistent with its sealing obligations and
    attempted in good faith to rectify its sealing error once
    it was discovered. The statutory objectives were essen-
    tially satisfied: The Government obtained valid judicial
    authorization for its wiretap intercepts, recorded the
    communications onto non-editable MO discs and sealed
    original copies of the MO discs with judicial authoriza-
    26        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    tion.17 The fact that a few of those tapes were defective
    was unknown until the Government’s investigation
    nearly was completed, and the sealing error certainly did
    not interfere with the statutory objectives of ensuring
    judicial oversight and non-tampering with wiretap re-
    cordings. Cf. Ojeda Rios, 
    495 U.S. at 266-67
     (concluding
    that the Government’s understanding of the law of exten-
    sions was erroneous but, nonetheless, did not interfere
    with the statutory objectives, and, thus, qualified as
    an objectively reasonable excuse for the Government’s
    sealing delay).
    Mr. Martin has not alleged that the Government ob-
    tained a tactical advantage by sealing the blank MO discs,
    that the Government procrastinated or otherwise acted
    in bad faith. Indeed, the record is completely devoid of
    any such evidence. Cf. United States v. Quintero, 
    38 F.3d 1317
    , 1328-30 (3d Cir. 1994) (rejecting the prosecutor’s
    heavy workload as a satisfactory explanation for a
    sealing delay because to do so “would be rendering
    extraordinary that which is ordinary”); United States v.
    Carson, 
    969 F.2d 1480
    , 1498 (3d Cir. 1992) (rejecting the
    need to enhance the audibility of tapes as a satisfactory
    explanation for a sealing delay because that need was
    17
    We have considered previously the reliability of MO discs
    and their non-editable characteristic. See United States v.
    McLee, 
    436 F.3d 751
    , 763-65 (7th Cir. 2006). The fact that the
    Government used MO discs in this case contributes to our
    conclusion that the sealing error is no cause for concern
    that tampering occurred.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         27
    “readily foreseeable and could just as readily become
    routine”). We believe the context in which the sealing
    error occurred in this case supports the Government’s
    explanation.
    Although the delay in sealing was significant—ap-
    proximately thirty-eight days for the reconstituted re-
    cordings, and never for the recordings that were lost,
    see supra note 7—the Government exhibited substan-
    tial compliance with the immediacy requirement by at-
    tempting to address the sealing error the same day the
    Government discovered that it had occurred. We agree
    with the district court that the delay in sealing is
    excusable under these circumstances. The charges in
    this case were unexceptional, and the record does not
    suggest that the defendants were particularly notorious.
    The Government had no unique incentive in this case
    to ignore intentionally its sealing obligations. See Coney,
    
    407 F.3d at 875
    .
    The Government had well-established procedures in
    place to ensure compliance with its sealing obligations,
    a consideration that contributes to the believability of
    the Government’s explanation. Cf. 
    id.
     (noting that the
    Assistant United States Attorneys had established a
    procedure for complying with their statutory sealing
    duties). For example, although the Government was
    obligated to seal the wiretap recordings only upon the
    expiration of the final extension period for Messrs. Martin’s
    and Simmons’s phones, see 
    18 U.S.C. § 2518
    (8)(a), the
    Government sealed the MO discs upon the completion
    of each thirty-day authorized period, see R.882 at 2. In
    28        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    this regard, the Government followed established Depart-
    ment of Justice protocols.1 8
    Finally, we agree with the district court’s conclusion
    that the blank-sealed recordings were of relatively minor
    importance to the Government’s case. The Government’s
    voluntary suppression of the recordings themselves
    indicates how small a role they played in the Govern-
    ment’s case against Mr. Martin. Although our review of
    the probable cause affidavit excerpts reveals that the
    contents of the blank-sealed recordings were used to
    obtain certain wiretap extensions, they were hardly
    the linchpin of these affidavits. Furthermore, the blank-
    sealed recordings were a small subset of the wire-
    tap recordings the Government created in this case,
    most of which were sealed properly. The blank-sealed re-
    cordings’ minimal importance contributes to our conclu-
    sion that the Government’s explanation is satisfactory.
    The Government provided a satisfactory explanation
    in this case and therefore no evidence was excludable
    under § 2518(8)(a). We therefore affirm the ruling of the
    district court that the Government’s explanation was
    satisfactory.
    18
    See Department of Justice’s Electronic Surveillance Manual
    28-30 (June 2005), available at http://www.justice.gov/criminal/
    foia/docs/elec-sur-manual.pdf (encouraging Assistant United
    States Attorneys to seal wiretap recordings at the completion
    of each authorized thirty-day period, irrespective of whether
    an extension is obtained).
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265           29
    B. Sixth Amendment Challenges
    1.
    Messrs. Martin, Bell and Terrell contend that the
    district court violated their Sixth Amendment rights
    by limiting their ability to cross-examine James Rudy
    Taylor (“Rudy”). Rudy was a member of the Mafia
    Insanes who worked for Mr. Simmons and managed
    a drug spot. Rudy was a named defendant in the indict-
    ment.19 He eventually pleaded guilty and entered into
    a cooperation plea agreement with the Government
    whereby he agreed to testify against Messrs. Martin, Bell
    and Terrell, among others, in exchange for a Government
    recommendation that he receive a reduced sentence.
    See R.737-38, 764.
    During the Martin/Bell trial,2 0 defense counsel informed
    the district court that the defense intended to cross-exam-
    ine Rudy about his involvement in a pending state
    murder investigation being conducted by the Police
    Department in Maywood, Illinois. Defense counsel knew
    that, when Rudy was arrested by federal agents for his
    role in the Mafia Insanes conspiracy, the Government
    had made Rudy available to the Maywood Police for
    19
    Rudy was charged in Count One (the conspiracy charge), and
    also with two firearm counts, in violation of 
    18 U.S.C. §§ 922
    (g)(1) and 922(k), and one count of using a telephone
    to facilitate a narcotics conspiracy, in violation of 
    21 U.S.C. § 843
    (b).
    20
    As noted above, Messrs. Martin and Bell were tried
    separately from Mr. Terrell.
    30         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    questioning. Defense counsel believed that Rudy had
    given a statement to the Maywood police concerning
    his involvement in the murder of an individual named
    Curtis Rios.21 Defense counsel asked the district court
    to permit cross-examination of Rudy about whether
    he expected to receive any benefit in the state murder
    investigation in return for giving testimony in the Mar-
    tin/Bell trial.
    21
    A defense counsel explained his understanding of the
    Maywood investigation and the statement as follows,
    [Rudy] gave a confession—that’s my word—a state-
    ment on May 20th, 2004, when he was picked up,
    basically, on another case, which was a murder, and
    this case.
    . . . [T]his confession that he gave, . . . is five pages in
    length, handwritten, signed by him . . . .
    My reading of it is that it was over a drug debt—or,
    I am sorry—over some drugs; that it has to do with a
    spot regarding the Mafias; that he shot this individual
    in the foot, and then unloaded the gun on him; that
    he went ahead, this individual, whose name is Curtis
    Rios, . . . a/k/a “Cheese,” who died the next day.
    [Rudy] . . . went ahead and got rid of his own gun
    almost immediately thereafter and kept or held on to
    Cheese’s gun for something like a month. I think that
    he basically says he had nine rounds and he emptied it.
    We don’t have an autopsy report. We don’t have
    those kinds of things, Judge.
    Trial Tr. at 1604-05, Sept. 18, 2006.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265          31
    The Government contended that the defense should not
    be permitted to question Rudy about the pending state
    murder investigation. The Government said that it
    had arranged no benefit for Rudy with the Maywood
    investigators in exchange for his cooperation in the
    federal case. According to the Government, the federal
    investigators had “talked with Maywood about working
    some type of concurrent deal. They were unwilling to do
    it, so we didn’t do anything with it. That’s it.” Trial Tr. at
    1606, Sept. 18, 2006. The Government argued that under
    Federal Rule of Evidence 609, the Maywood murder
    investigation was not a proper subject for cross-examina-
    tion because Rudy had not been convicted;2 2 nor was it
    admissible under Rule 608(b) because the alleged offense
    “has nothing to do with truth-telling.” 
    Id. at 1607
    . The
    Government also informed the defense and the district
    court that, if asked about the Maywood murder inves-
    tigation, Rudy intended to invoke his Fifth Amend-
    ment right not to incriminate himself. 
    Id. at 1605
    .
    The district court stated, “Whether it’s a murder or a
    traffic offense, if it’s an arrest, it’s not admissible unless
    there is a benefit given. And I understand, from what
    everybody tells me, there has not been a benefit given.”
    
    Id. at 1606
    . The district court also noted that the state-
    ment given to the Maywood investigators could be used
    by the defense to impeach Rudy if he testified about the
    22
    The defense and the Government agreed that Rudy had not
    been charged with the murder of Curtis Rios. See Trial Tr.
    at 1606, Sept. 18, 2006.
    32        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Maywood murder on direct. 
    Id. at 1607
    . However, the
    district court did not know whether that contingency
    would occur. It therefore permitted a voir dire of Rudy
    to determine whether he intended to testify about the
    Maywood murder and whether he expected to receive
    any benefit in that case in exchange for his cooperation
    in the federal action. 
    Id. at 1607-08
    .
    A voir dire was conducted. Defense counsel asked
    Rudy if he had given a statement concerning the murder
    of Curtis Rios. Rudy declined to answer, invoking the
    Fifth Amendment. 
    Id. at 1610
    . Defense counsel then
    asked Rudy whether he expected to receive any benefit
    from the Government in exchange for his cooperation
    in the federal action. Rudy said that he expected to
    receive no benefits. 
    Id. at 1610-15
    .
    At a sidebar, the district court told defense counsel,
    If you can establish that [Rudy] has an expecta-
    tion that he is getting a pass on something out in
    Maywood as a result of his testimony here, I will
    then allow you to ask about what it is out in
    Maywood that he thinks he is getting a pass on.
    But until that predicate has been laid, there is
    no basis to inquire into this.
    And I will just tell you, the 403 balancing goes
    in favor of the government as well. I’m not—
    I don’t think it’s appropriate to ask about this, as
    I understand it, unrelated murder.
    
    Id. at 1622
    . Defense counsel contended that the May-
    wood murder was related to the drug activity charged
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         33
    in the federal indictment. 
    Id.
     Defense counsel wanted
    to clarify whether Rudy intended to invoke the Fifth
    Amendment if asked about the murder. 
    Id. at 1623
    . The
    district court stated, “I don’t think there is any basis,
    from what I have heard right now, that we ought to
    even open the door to his taking the Fifth on this.
    Nor do I think there is any particular benefit to the defen-
    dants in letting the jury know that there was a gang-
    related murder.” 
    Id. at 1627
    . The district court proposed
    that defense counsel focus its voir dire questions on
    whether Rudy expected any deal from the Maywood
    investigators. 
    Id.
    Instead, defense counsel asked Rudy about his plea
    agreement with the Government and what he expected
    to gain from testifying in the Martin/Bell trial. 
    Id. at 1628
    . Obviously confused by defense counsel’s ques-
    tions, Rudy said he expected to receive no benefits at all.
    
    Id.
     The district court interjected and asked Rudy if he
    understood that, in the written plea agreement with the
    Government, the Government agreed to recommend a
    reduced sentence for Rudy in the federal action in
    return for his cooperation. 
    Id.
     Rudy confirmed that that
    was his understanding, and he indicated that he under-
    stood that the Government’s favorable recommendation
    at his sentencing hearing would depend on whether
    he told the truth during his trial testimony. 
    Id. at 1628-29
    .
    The district court asked Rudy,
    [H]ave you received any other agreement from the
    government? Have they offered you anything
    else? . . . Has the government offered you any
    34        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    benefits in any other case? . . . Has the government
    offered to do anything for you in connection
    with any other charges? . . . Is it your expectation
    or hope that the government is going to do some-
    thing in some other case for you?
    
    Id. at 1629-30
    . Rudy answered no to each of those ques-
    tions. 
    Id.
    Defense counsel then resumed the voir dire questioning
    and asked Rudy if it was his “understanding that a mem-
    ber of the U.S. Attorney’s Office called the State’s Attor-
    ney’s office out in Maywood?” 
    Id. at 1630
    . Rudy said no.
    
    Id.
     Defense counsel asked, “Did your lawyer talk to
    you at all about any efforts on the part of the U.S. Attor-
    ney to work out your case, your prospective case, in
    Maywood?” 
    Id.
     The district court interjected and said,
    “I want to tell the witness that he has permission not
    to answer questions about communication with his
    lawyer . . . . It doesn’t relate to the Fifth Amendment.
    It’s an independent privilege.” 
    Id. at 1630-31
    . Defense
    counsel then asked Rudy, “Sir, do you expect to be
    charged out in Maywood?” 
    Id. at 1631
    . The Government
    objected and complained that the question “go[es] back
    to the statement again.” 
    Id.
     The district court sustained
    the objection and said, “I think we should bring the
    jurors in. We are not going to pursue this line of ques-
    tioning in the jurors’ presence unless the witness’ testi-
    mony changes.” 
    Id.
    Defense counsel sought to clarify the ruling and
    asked, “Judge, are we precluded from any other ques-
    tions about benefits when he is on the stand?” 
    Id. at 1632
    .
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265      35
    The district court stated, “No. You are welcome to
    ask questions about benefits, without reference to this—.”
    
    Id.
     Unsatisfied, defense counsel sought permission to
    continue the voir dire and ask additional questions
    about the Maywood murder, which the court allowed.
    The following colloquy occurred:
    [DEFENSE COUNSEL]: Are there any outstanding
    offenses that you are concerned about the Judge
    knowing about at this point?
    [THE GOVERNMENT]: Objection, Judge. It’s forc-
    ing this witness to take Five on this again.
    [DEFENSE COUNSEL]: I am not asking him to
    take Five. I am only asking him whether or not
    he is concerned about it.
    [THE GOVERNMENT]: If he says yes, the next
    question is what offenses? Judge. And then we
    are back to the statement.
    [DEFENSE COUNSEL]: That wasn’t going to be
    my next question, Counsel.
    [THE GOVERNMENT]: If he says he is con-
    cerned, it also is potentially admissible.
    THE COURT: Look, there are ways that you can
    ask questions that would elicit this. I have made
    a 403 decision here that we ought not proceed
    down this line. So questions that are designed
    to elicit evidence concerning the episode in May-
    wood, I am going to sustain those objections,
    unless there is an indication that the wit-
    36        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    ness has a genuine expectation of a benefit
    in connection with that. And there has been
    no such showing.
    
    Id. at 1634
    .
    Still unsatisfied, defense counsel sought permission
    to continue the voir dire and ask additional ques-
    tions about benefits Rudy expected to receive from his
    cooperation. The district court allowed further ques-
    tioning. Defense counsel asked Rudy about his plea
    agreement, and Rudy confirmed that it was his under-
    standing that, in return for his guilty plea and truthful
    testimony in the federal action, the Government would
    recommend that he receive a lower sentence. 
    Id. at 1636
    .
    The Government asked to clarify the record and asked
    Rudy, “Sir, if you have cases out in Maywood, or poten-
    tial cases, do you understand that by cooperating with
    the government that those will go away?” 
    Id.
     Rudy an-
    swered, “No.” 
    Id. at 1637
    . Defense counsel then
    asked, “Do you expect the government to do anything
    whatsoever to try to help you in that potential case in
    Maywood?” 
    Id.
     Rudy responded, “I refuse to answer,
    your Honor. . . . I plead the Fifth.” 
    Id.
     Defense counsel
    said, “That’s the crux of this, Judge. . . . That’s it.” 
    Id.
     The
    district court stated, “It isn’t the crux. The witness has
    testified about this matter. I don’t think we should
    pursue it any longer.” 
    Id.
     The voir dire ended.
    The trial resumed, and Rudy testified on behalf of the
    Government, describing his role in Mr. Simmons’s drug
    operation and, more generally, the involvement of the
    Mafia Insanes gang. See 
    id. at 1645, 1669-71, 1679-81
    .
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265     37
    Defense counsel did not cross-examine Rudy about the
    Maywood murder investigation. However, defense
    counsel attempted to impeach Rudy in other ways. For
    example, defense counsel asked Rudy about his prior
    arrests and about aliases that he had given to the
    police during those arrests. See 
    id. at 1706-08
    . Defense
    counsel also asked Rudy about his prior drug abuse. See
    
    id. at 1715-17
    . Defense counsel asked Rudy why he left
    certain information out of his proffer statement given
    to the DEA. See 
    id. at 1721-22
    . Defense counsel also
    asked Rudy about minor inconsistencies in his testi-
    mony. See 
    id. at 1763
    . Finally, defense counsel asked
    Rudy about the plea agreement with the Government;
    Rudy confirmed that, if he testified truthfully, the Gov-
    ernment would dismiss certain charges pending against
    him and recommend that he be sentenced at a level one-
    third below the low end of his applicable Guidelines
    range. See 
    id. at 1723-26, 1732-37
    .
    The trial continued, and other witnesses offered testi-
    mony that further incriminated the defendants.
    Messrs. Martin and Bell ultimately were convicted
    and sentenced.
    2.
    Approximately a year after the Martin/Bell trial had
    concluded, Mr. Terrell was tried separately, and the
    Government again called Rudy as a cooperating witness.
    The Government reminded the district court about the
    substance of Rudy’s testimony in the Martin/Bell trial.
    38        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    The Government asked for the same evidentiary ruling
    barring cross-examination concerning the Maywood
    murder investigation. The district court asked defense
    counsel if she objected, to which she responded, “[T]he
    only thing I would ask is for another voir dire so we
    can talk to him and make sure he doesn’t think that
    this murder that he confessed to is in any way associ-
    ated with the deal he is getting from the government.”
    Trial Tr. at 341, Jul. 12, 2007. The district court asked
    the Government to begin, and the following voir dire
    occurred:
    [BY THE GOVERNMENT:]
    Q. [Rudy], you were questioned by people from
    the Maywood Police Department about a
    shooting, weren’t you?
    A. Yes, sir.
    Q. You have got a cooperation deal in this case,
    don’t you?
    A. Yes, sir.
    Q. Do you understand that cooperation deal to
    have taken care of any possible situation you have
    in Maywood?
    A. No, sir.
    Q. Do you know if the United States Attorney’s
    Office or DEA or anybody reached out to
    Maywood to, I guess for lack of a better term,
    make that case go away?
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         39
    A. No, sir.
    Q. What is your cooperation agreement—what
    charges do you understand your cooperation
    agreement to take care of or resolve?
    A. Contending this case here that I am on.
    Q. Just this case?
    A. Yes.
    Q. Does it take care of any other possible charges?
    A. No, not to my knowledge.
    [THE GOVERNMENT:] I don’t have any further
    questions, your Honor.
    [THE COURT:]      Any cross-examination . . . ?
    [DEFENSE COUNSEL:] Thank you.
    [BY DEFENSE COUNSEL:]
    Q. Have you       been   charged   with   stuff   in
    Maywood?
    A. I plead the Fifth on that.
    Q. Do you know if any charges have been filed
    against you?
    A. Yes, sir—yes, ma’am.
    Q. They have been filed against you?
    A. The charges that I am up against now.
    Q. In Maywood, out of that?
    A. I plead the Fifth on that.
    40        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    [DEFENSE COUNSEL:] Your Honor, I think he
    waived it by answering their questions. And now
    to invoke it for just this limited part—
    [THE GOVERNMENT:] Judge, if I can just step in
    for a moment.
    [Rudy’s counsel] was here this morning. I abso-
    lutely do not want to get into what [she and
    Rudy] talked about . . . but it would be—I guess
    I understand that this is not an area where he
    is going to be willing to answer any questions on.
    Maybe it makes sense to get [Rudy’s counsel]
    here if this is going to be something that we need
    to go into, but my sense is we have covered this
    ground already. Nothing has changed since then.
    [THE COURT:] Here is what I want to do. I am
    going to bring the jury back right now, and what
    we can do with respect to this issue is get [Rudy’s
    counsel] over here, see whether that changes
    anything with respect to whether or not he is
    willing to answer the question about whether
    charges have been filed. And if we need to reopen
    his testimony for some reason, we can do that.
    
    Id. at 342-44
    . Mr. Terrell’s defense counsel did not object
    to that plan.
    The trial resumed and Rudy testified about Mr. Terrell’s
    role in the Mafia Insanes conspiracy. Defense counsel did
    not cross-examine Rudy about the Maywood murder
    investigation. However, defense counsel impeached
    Rudy by asking him about prior inconsistent statements
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265           41
    that he had given to police and agents, see 
    id. at 381-83
    , 386-
    87, his prior charges, see 
    id. at 387-90
    , and about his
    plea agreement with the Government, see 
    id. at 400-02
    .
    Rudy’s testimony concluded, and he was excused.
    Later in the trial, the district court returned to the
    issue of Rudy’s testimony and summoned Rudy for an
    additional voir dire. Rudy’s counsel appeared and the
    following exchange occurred:
    [BY THE GOVERNMENT:]
    Q. I just have a few questions for the purpose of
    follow-up.
    [Rudy], we talked about your plea agreement
    previously. Do you understand that coopera-
    tion/plea agreement that you have to extinguish
    or take care of any potential cases that might
    arise in Maywood, Illinois?
    A. No, sir.
    Q. And so do you understand that you received
    a benefit regarding anything that might have
    happened in Maywood, Illinois from the United
    States Attorney’s Officer in connection with
    your plea agreement?
    A. No, sir.
    [THE GOVERNMENT:] No             further questions,
    Your Honor.
    The Court: Cross-examination?
    [DEFENSE COUNSEL:] Thank you.
    ....
    42        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    [BY DEFENSE COUNSEL:]
    Q. Now, the case that we’re talking about is a
    case in Maywood involving a murder, correct?
    A. Yes, yes, ma’am.
    Q. And you were questioned about that murder
    the day you were arrested on this case, right?
    [RUDY’S COUNSEL:] Your Honor—
    BY THE WITNESS:
    A. Plead the Fifth.
    [RUDY’S COUNSEL:] —I would object to this.
    I think that [Rudy] has a right to exercise his
    Fifth Amendment if we’re going to talk about the
    statement.
    THE COURT: Well, the question was: Were you
    questioned about that Murder?
    [DEFENSE COUNSEL:] Yeah, I’m not going to
    get into—
    THE COURT: Overruled. You may answer.
    Were you questioned about that murder when
    you were arrested back in ‘04 in this case?
    BY THE WITNESS:
    A. I was asked about it.
    [BY DEFENSE COUNSEL:]
    Q. Okay. And have you been—are there any
    charges resulting from that murder against you
    currently?
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265       43
    A. No, ma’am.
    Q. Okay. So you—do you have any cases at all
    pending anywhere else but the case that’s here
    right now?
    A. Traffic, traffic, ma’am.
    Q. Okay. Now, are you aware if the federal gov-
    ernment has spoken to any of the assistant state’s
    attorneys out in Maywood regarding that case?
    A. No, ma’am.
    Q. Do you believe that you are going to be in-
    dicted in that Maywood case?
    A. No, ma’am.
    Q. Do you believe that your cooperation in this
    case, meaning your testimony against other
    people in this case and in other federal cases, is
    going to help you so you won’t be charged in
    that Maywood case?
    A. No, ma’am.
    [DEFENSE COUNSEL:] Nothing further.
    THE COURT: All right. Do we need to take any
    further steps with this witness?
    [DEFENSE COUNSEL:] I do not.
    Trial Tr. at 566-69, Jul. 16, 2007. The voir dire con-
    cluded, and Rudy was excused. The trial resumed, and
    Mr. Terrell’s defense counsel did not raise the Rudy cross-
    examination issue again. Mr. Terrell ultimately was
    convicted.
    44       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Mr. Terrell filed a post-trial motion for acquittal, con-
    tending that the district court’s earlier ruling circum-
    scribed improperly his cross-examination of Rudy. See
    R.1875. The motion stated that Mr. Terrell was pre-
    vented from determining whether Rudy “may have had
    [a subjective belief] regarding any promise the state
    made to him regarding possible murder charges not
    being brought in exchange for his testimony in this con-
    spiracy trial.” 
    Id. at 1
    . The motion continued, “In light
    of the fact [that Rudy] was arrested on this conspiracy
    charge and immediately brought to the Maywood Police
    Department in reference to the murder charge, the sub-
    stance of the conversation [he] had with the Maywood
    police would be relevant as to the reasonableness of his
    subjective belief.” 
    Id. at 2
    . The motion did not allege
    specifically that the district court’s ruling violated
    Mr. Terrell’s constitutional rights.
    Soon thereafter, Mr. Terrell substituted counsel, and
    his new counsel filed an amended post-trial motion,
    renewing the contention that the district court’s ruling
    limiting the cross-examination of Rudy about the May-
    wood murder investigation was erroneous. Specifi-
    cally, Mr. Terrell contended, “By denying Mr. Terrell
    the right to investigate this weakness in [Rudy’s] testi-
    mony, the [district court] violated Mr. Terrell’s right
    under the Confrontation Clause. U.S. Const. Amnd. V
    [sic].” R.1890 at 3.
    The Government opposed the motion, contending that
    Mr. Terrell had waived his opportunity to challenge the
    district court’s ruling. See R.2026 at 9. The Government
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265        45
    noted that, when it had sought the same evidentiary
    ruling that the district court had made in the previous
    Martin/Bell trial, Mr. Terrell’s trial counsel never ob-
    jected and only requested that a voir dire occur. See 
    id. at 10
    . The Government stated that “defense counsel even
    confirmed after the voir dire that the voir dire questioning
    was all that counsel sought.” 
    Id.
     at 11 (citing Trial Tr. at
    569, Jul. 16, 2007). The Government further argued that,
    in any event, Mr. Terrell’s complaint was meritless
    because Rudy had denied any expectation of benefit
    related to the Maywood murder investigation and that
    Rudy’s alleged motive to lie was purely speculative. 
    Id. at 11-12
    . The Government also contended that “cross-
    examination on this topic would [have] . . . cause[d] much
    confusion and waste of time,” “precisely the sort of
    confusion and waste that Federal Rule of Evidence 403
    would prohibit.” 
    Id.
     The Government noted that “[o]f
    course, [the district court] did not even have to make
    a specific Rule 403 determination during Terrell’s trial
    because he waived the issue after the satisfactory voir
    dire.” 
    Id. at 12
    .
    The district court denied the motion; it ruled that
    Mr. Terrell’s right to confrontation had not been violated
    by the ruling limiting cross-examination of Rudy. See
    R.2130. The district court explained, “The right of con-
    frontation does not require that a defendant be per-
    mitted to explore any and all avenues of bias. Nor
    was [Rudy’s] testimony the only (or even the most
    important) evidence against the Defendant. The court
    concludes that a new trial is not warranted due to this
    evidentiary ruling.” 
    Id. at 2
     (internal citations omitted).
    46       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    3.
    Messrs. Martin, Bell and Terrell appeal the district
    court’s rulings limiting their ability to cross-examine
    Rudy about the Maywood murder investigation. They
    contend that the Sixth Amendment guaranteed them
    the right to cross-examine Rudy in front of the jury
    about whether he was biased in favor of the prosecutors
    because of his desire to secure their assistance with
    the pending Maywood murder investigation. See Mar-
    tin/Bell Appellant’s Br. 9-10; Terrell Appellant’s Br. 13.
    The defendants suggest that they should have been per-
    mitted to establish the following facts before the jury:
    “1) that [Rudy] was suspected of murder in state
    court; 2) that [Rudy] had not yet been prosecuted for
    that murder; 3) that [Rudy] was first informed of that
    murder investigation immediately following his arrest
    by the federal government in this case; 4) that the fed-
    eral authorities delivered [Rudy] to the state officials
    for interrogation regarding that murder; 5) that [Rudy]
    had made a statement to state authorities admitting
    his involvement in the murder; and 6) that [Rudy] was
    never prosecuted for the murder to which he confessed
    after he began cooperating with federal authorities.”
    Martin/Bell Appellant’s Br. 10. They explain that, “[b]ased
    on these facts, a reasonable juror could infer that [Rudy]
    was manufacturing incriminating testimony against
    the defendant-appellants in order to minimize his culpa-
    bility in the investigation and avoid prosecution for
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         47
    the murder.” Id.; see also 
    id. at 13-14, 17-19
    .2 3
    Messrs. Martin, Bell and Terrell emphasize that Rudy’s
    alleged bias arising from his expectation of a benefit
    in the Maywood murder investigation was a “core”
    concern of the Sixth Amendment because it represented
    “an entire source of bias” that the jury never heard about.
    
    Id. at 11-14
    . They point to Delaware v. Van Arsdall, 
    475 U.S. 673
     (1986), and Davis v. Alaska, 
    415 U.S. 308
     (1974), deci-
    sions establishing that cross-examination regarding a
    witness’s bias created by the threat of prosecution for
    matters unrelated to the crime about which the witness
    testifies is a core concern of the Sixth Amendment. See
    Martin/Bell Appellant’s Br. 14. They contend that all
    of Rudy’s testimony should have been stricken or
    a mistrial declared because Rudy relied on the Fifth
    Amendment when he was asked about the Maywood
    murder investigation. Id. at 21-23. They believe that
    Rudy’s bias was a core concern of the Sixth Amendment,
    and, therefore, his Fifth Amendment right should not
    have trumped the defendants’ Sixth Amendment rights.
    The Government contends that the Sixth Amendment
    does not guarantee an unfettered right to cross-examine
    23
    The defendants do not contend that the Government
    violated its disclosure obligations by withholding any infor-
    mation about the Maywood murder investigation. They base
    their theory that Rudy was inclined to fabricate testimony
    in favor of the Government entirely on the facts brought
    out during the pretrial and trial proceedings and inferences
    drawn from those facts.
    48        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    and that the right may be limited by courts to avoid
    causing prejudice, confusion or delay. Appellee’s Br. 31.
    In the Government’s view, the Maywood murder investi-
    gation was strictly a collateral matter because there was
    no evidence showing that Rudy expected or hoped
    for any benefit in the Maywood murder investigation.
    Id. at 31-32. The Government notes that the defendants
    had ample opportunity to and did establish Rudy’s
    bias arising from his cooperation plea agreement and
    that the defendants impeached Rudy by asking him
    about his prior convictions and inconsistent state-
    ments. Id. at 31-32, 34-35. Additionally, the Government
    contends that Rudy’s invocation of his Fifth Amendment
    right not to incriminate himself insulated the district
    court’s ruling circumscribing questioning about the
    Maywood murder investigation; the Government be-
    lieves that such questioning involved a collateral matter
    and therefore paled in comparison to Rudy’s important
    Fifth Amendment right. Id. at 33, 36.2 4
    24
    Additionally, the Government renews its contention, which
    it made to the district court, but which the district court did
    not rule on, that Mr. Terrell “failed to object to Rudy’s testi-
    mony and thus forfeited [his Sixth Amendment] claim.” Appel-
    lee’s Br. 30 n.10. We disagree with the Government’s character-
    ization of the record. Although Mr. Terrell’s counsel did not
    specifically articulate a Sixth Amendment objection during
    the trial, counsel evinced an intention to cross-examine Rudy
    about the Maywood murder investigation in order to show
    Rudy’s bias in favor of the Government. Furthermore,
    (continued...)
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         49
    4.
    The Sixth Amendment to the Constitution of the
    United States ensures that a defendant be given an op-
    portunity for effective cross-examination. See Pennsyl-
    vania v. Ritchie, 
    480 U.S. 39
    , 51-53 (1987); Delaware v. Van
    Arsdall, 
    475 U.S. 673
    , 678-79 (1986). Nevertheless, trial
    courts retain wide discretion to impose reasonable
    limits on cross-examination in order to curb harass-
    ment, prejudice, confusion of issues, threats to witness
    safety and testimony that is repetitive and only
    marginally relevant. Van Arsdall, 
    475 U.S. at 679
    ; United
    States v. Smith, 
    454 F.3d 707
    , 714 (7th Cir. 2006).
    When a district court’s limitation of cross-examina-
    tion directly implicates the values protected by the Con-
    frontation Clause of the Sixth Amendment, we review
    the district court’s ruling de novo; otherwise, we review
    the district court’s limitation of cross-examination under
    the more deferential abuse of discretion standard. See
    Smith, 
    454 F.3d at 714
    . At issue here is the district court’s
    limitation of the defendants’ cross-examination of Rudy
    about his alleged pro-Government bias because of a desire
    to curry favorable treatment in connection with the
    Maywood murder investigation. “Bias is a term used
    in the ‘common law of evidence’ to describe the rela-
    24
    (...continued)
    Mr. Terrell’s post-trial motion amplified the constitutional
    arguments in support of that issue. The objection was suffi-
    ciently preserved. See United States v. Glover, 
    479 F.3d 511
    ,
    517 n.1 (7th Cir. 2007).
    50        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    tionship between a party and a witness which might
    lead the witness to slant, unconsciously or otherwise, his
    testimony in favor of or against a party.” United States v.
    Abel, 
    469 U.S. 45
    , 52 (1984). Cross-examination designed
    to elicit witness bias directly implicates the Sixth Amend-
    ment. See Abel, 
    469 U.S. at 49-52
    ; Davis v. Alaska, 
    415 U.S. 308
    , 316-17 (1974); Alford v. United States, 
    282 U.S. 687
    ,
    691-92 (1931). Consequently, our review is de novo. If a
    Sixth Amendment violation occurred, we shall set aside
    the verdict unless the Government establishes that the
    error was harmless beyond a reasonable doubt. See Van
    Arsdall, 
    475 U.S. at 684
    ; United States v. Nelson, 
    39 F.3d 705
    , 710 (7th Cir. 1994).
    The exposure of a witness’s bias directly implicates
    the Sixth Amendment. See Abel, 
    469 U.S. at 52
     (“Proof of
    bias is almost always relevant because the jury, as finder
    of fact and weigher of credibility, has historically been
    entitled to assess all evidence which might bear on the
    accuracy and truth of a witness’ testimony.”). As we
    noted in United States v. Recendiz, 
    557 F.3d 511
    , 530 (7th
    Cir. 2009), “[a] core value [of the Sixth Amendment]
    is the ability to expose a witness’s motivation for testi-
    fying, his bias, or his possible incentives to lie.” Proof of
    bias “is the ‘quintessentially appropriate topic for cross-
    examination.’ ” United States v. Manske, 
    186 F.3d 770
    , 777
    (7th Cir. 1999) (quoting Bachenski v. Malnati, 
    11 F.3d 1371
    , 1375 (7th Cir. 1993)).
    We believe that the situation before us today clearly
    implicates the defendants’ rights to meaningful cross-
    examination with respect to witness bias. The Govern-
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265          51
    ment had made Rudy available to state prosecutors
    for questioning about the Maywood murder. Rudy con-
    ceded that he had given a statement to those prosecutors
    with respect to that murder and that he never was
    charged with that murder. He denied the existence of a
    quid pro quo with the state or federal prosecutors. The
    district court took the view that the Maywood murder
    was “unrelated” to the issues on trial. See Trial Tr. at 1622,
    Sept. 18, 2006 (“I’m not—I don’t think it’s appropriate
    to ask about this, as I understand it, unrelated murder.”).
    We respectfully take a different view from the one
    taken by our colleague in the district court. Upon exam-
    ination, the record makes clear that defense counsel
    sufficiently articulated a link between Rudy’s involve-
    ment in the pending state murder investigation and his
    testimony in the federal action. The conceded facts
    that Rudy was interrogated by state investigators soon
    after he was arrested, that he gave a statement about
    the murder of Curtis Rios and that he might have been
    charged with the murder—a serious offense that carries
    a severe punishment—could have been linked to
    Rudy’s decision to cooperate with the Government in
    this action. Cf. Lindh v. Murphy, 
    124 F.3d 899
    , 901 (7th Cir.
    1997) (“[The witness] may have believed that testimony
    helping the prosecution in this case, which achieved
    notoriety throughout Wisconsin, would aid his [unre-
    lated, pending criminal] cause, if only because it was
    bound to come to the attention of the judge who
    presided in the prosecution against him.”); United States
    v. Anderson, 
    881 F.2d 1128
    , 1139 (D.C. Cir. 1989) (“To
    require evidence of an actual cooperation agreement
    52         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    between [the Government] and [the allegedly biased
    witness], as the district court in this case did, overlooks
    the inherent and independent relevance of the mere fact
    of a recently dismissed murder charge, a charge
    which hung over the witness’ head like the sword of
    Damocles . . . .” (emphasis in original)). We believe the
    established facts were probative of Rudy’s possible bias.
    He had been implicated in the murder, he had been
    subject to the investigation, he had not been charged
    and there was no indication that the investigation was
    closed.
    The mere fact that Rudy denied the existence of
    an agreement not to prosecute him for the state murder
    in return for his testimony against the defendants
    does not end the matter. The defendants were entitled
    to meaningful cross-examination on the question of bias
    so that the jury could assess fully his testimony. As we
    see it, the district court’s ruling placed counsel for the
    defendants in a predicament not unlike the situation
    facing counsel in Davis:
    We cannot accept the Alaska Supreme Court’s
    conclusion that the cross-examination that was
    permitted defense counsel was adequate to de-
    velop the issue of bias properly to the jury. While
    counsel was permitted to ask [the witness] whether
    he was biased, counsel was unable to make a
    record from which to argue why [the witness]
    might have been biased or otherwise lacked
    that degree of impartiality expected of a witness
    at trial. On the basis of the limited cross-examination
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265                   53
    that was permitted, the jury might well have thought
    that defense counsel was engaged in a speculative and
    baseless line of attack on the credibility of an apparently
    blameless witness[2 5 ] or, as the prosecutor’s objec-
    tion put it, a ‘rehash’ of prior cross-examination.
    On these facts it seems clear to us that to make
    any such inquiry effective, defense counsel should
    have been permitted to expose to the jury the
    facts from which jurors, as the sole triers of fact
    and credibility, could appropriately draw infer-
    ences relating to the reliability of the witness.
    Petitioner was thus denied the right of effective
    cross-examination which would be constitu-
    tional error of the first magnitude and no amount
    of showing of want of prejudice would cure it.
    
    415 U.S. at 318
     (emphasis, other than the one accompany-
    ing note 25, in original; internal quotation marks omitted).
    Rudy’s alleged bias was more uncertain than the bias
    alleged in Van Arsdall, and, perhaps, was even more
    uncertain than the alleged bias in Davis. Nevertheless, it
    was not so speculative as to make defense counsel’s
    attempt to demonstrate it fall outside the guarantee of
    the Sixth Amendment.
    There are, of course, limits to the Sixth Amendment
    guarantee of the opportunity to question a witness
    about his bias. As the Supreme Court has stated:
    “[T]he exposure of a witness’ motivation in tes-
    tifying is a proper and important function of
    25
    This emphasis added.
    54         Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    the constitutionally protected right of cross-ex-
    amination.” [Davis, 
    415 U.S. at 316-17
    ]. It does not
    follow, of course, that the Confrontation Clause
    of the Sixth Amendment prevents a trial judge
    from imposing any limits on defense counsel’s
    inquiry into the potential bias of a prosecution
    witness. On the contrary, trial judges retain wide
    latitude insofar as the Confrontation Clause is
    concerned to impose reasonable limits on such
    cross-examination based on concerns about,
    among other things, harassment, prejudice, confu-
    sion of the issues, the witness’ safety, or interroga-
    tion that is repetitive or only marginally relevant.
    And as we observed earlier this Term, “the Con-
    frontation Clause guarantees an opportunity for
    effective cross-examination, not cross-examina-
    tion that is effective in whatever way, and to
    whatever extent, the defense might wish.” Delaware
    v. Fensterer, 
    474 U.S. 15
    , 20 (1985).
    ....
    . . . We think that a criminal defendant states a
    violation of the Confrontation Clause by showing
    that he was prohibited from engaging in other-
    wise appropriate cross-examination designed
    to show a prototypical form of bias on the part
    of the witness, and thereby “to expose to the jury
    the facts from which jurors . . . could appropriately
    draw inferences relating to the reliability of the
    witness.” [Davis, 
    415 U.S. at 318
    ].
    Van Arsdall, 
    475 U.S. at 678-80
     (citations modified; em-
    phasis in original).
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265             55
    A bias theory may be so speculative that a court would
    be entitled to preclude its admission under Rule 403.2 6
    Here, however, although Rudy’s bias was denied
    by the Government and Rudy himself, the defendants
    articulated a reasonable argument to the contrary. The
    timing, nature and status of the Maywood murder inves-
    tigation was probative of bias and the defense had the
    right to explore it fully and allow the jury to draw its
    own conclusions.
    That the defendants were permitted to examine other
    matters relating to Rudy’s alleged bias, such as the
    written plea agreement and Rudy’s prior convictions,
    does not resolve the Sixth Amendment violation. Cf.
    Davis, 
    415 U.S. at 318
     (“We cannot accept the Alaska
    Supreme Court’s conclusion that the cross-examination
    that was permitted defense counsel was adequate to
    develop the issue of bias properly to the jury.”). The
    alleged bias arising out of the Maywood murder inves-
    tigation was a separate and independent area of bias,
    26
    See United States v. Given, 
    164 F.3d 389
    , 392 (7th Cir. 1999)
    (finding no error in a district court’s ruling precluding re-
    recross-examination about a witness’s unrequited romantic
    interest in the defendant because the issue was unsubstan-
    tiated and had been unpursued by the defense); United
    States v. Sinclair, 
    109 F.3d 1527
    , 1537-38 (10th Cir. 1997) (con-
    cluding that the defendant’s theory of witness bias lacked
    “factual support,” was “highly doubtful,” and, thus, fell
    within the district court’s Rule 403 discretion to limit cross-
    examination).
    56        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    which the defendants sufficiently had distinguished
    from the other areas of bias.
    We must conclude that the questions that the
    defendants were not permitted to ask were directly
    relevant to the jury’s assessment of Rudy’s possible bias.
    Accordingly, the restriction of the defendants’ cross-
    examination of Rudy violated their rights under the
    Sixth Amendment.
    5.
    We now examine whether the violations of Messrs.
    Bell’s and Terrell’s Sixth Amendment confrontation
    rights were harmless error. 2 7 Violations of the Sixth
    Amendment’s Confrontation Clause are subject to harm-
    less error review. See Van Arsdall, 
    475 U.S. at 684
    . “The
    correct inquiry is whether, assuming that the damaging
    potential of the cross-examination were fully realized,
    a reviewing court might nonetheless say that the error
    was harmless beyond a reasonable doubt.” 
    Id.
     “Whether
    an error is harmless beyond a reasonable doubt
    27
    Mr. Martin does not join in this argument. See Martin/Bell
    Appellants’ Br. 24 (contending only that Rudy’s testimony was
    necessary to convict Mr. Bell). Even if he had, we would find
    that the wealth of evidence presented against Mr. Martin
    renders the Sixth Amendment violation harmless. For example,
    at least three high-ranking members of the Mafia Insanes
    network, Donnell Simmons, Johnny Moore and Patrick Bray,
    testified about the practice of paying Mr. Martin street taxes
    collected from the Mafia Insanes controlled drug spots.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265           57
    depends upon factors such as the importance of the wit-
    ness’s testimony in the prosecution’s case, whether the
    testimony was cumulative, the presence or absence of
    corroborating or contradictory evidence and the overall
    strength of the prosecution’s case.” Smith, 
    454 F.3d at 715
    .
    Mr. Bell contends that Rudy’s testimony was the only
    evidence the Government offered linking him to the
    overarching Mafia Insanes conspiracy, as organized
    primarily by Mr. Martin.2 8 Mr. Bell concedes that evidence
    established that he was a ranking member of the Mafia
    Insanes street gang. However, he contends that “being a
    member of a gang is not the same as being a member of
    a drug conspiracy.” Martin/Bell Appellants’ Br. 25. For
    example, Mr. Bell argued to the jury that his payments
    of sizeable amounts of cash to Mr. Martin were
    personal loans among friends. Mr. Bell now contends
    that Rudy’s testimony was the only evidence the Gov-
    ernment offered establishing that those payments were
    street taxes collected from the drug spots controlled by
    the Mafia Insanes conspiracy.
    The Government contends that Rudy’s testimony was
    hardly necessary to establish that Mr. Bell joined the
    charged conspiracy. The Government notes that the
    jury heard Mr. Bell’s post-arrest statement:
    28
    See Martin/Bell Appellants’ Br. 24-25 (“[A]lthough [Mr. Bell]
    was a drug dealer he was not a member of Mr. Martin’s organi-
    zation and never had been in a conspiracy with Mr. Martin’s
    organization to distribute narcotics.” (emphasis in original)).
    58        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    I was affiliated with the Mafia Insane Vice Lords
    and I ran one drug spot on North Avenue in
    Chicago from 2000 until 2002 or 2003. I supervised
    other drug workers when I was running the
    drug spot on North Avenue. A Five Star Universal
    Elite is a high-ranking member of the Mafia
    Insane Vice Lords.
    Trial Tr. at 157, Sept. 5, 2006.
    Although Mr. Bell contends that this statement does
    not contain an admission that he paid a street tax to the
    king of the Mafia Insanes, other testimony directly ad-
    dresses this point. Rudy’s general testimony about
    the structure of the Mafia Insanes network, not at all
    specific to Mr. Bell’s participation, was really of little or
    no consequence to Mr. Bell’s conviction. The jury had
    substantial evidence from which to understand the net-
    work and to assess Mr. Bell’s involvement in the
    charged conspiracy. The evidence overwhelmingly
    showed that Mr. Bell agreed with other members of
    the conspiracy to distribute narcotics. The violation of
    Mr. Bell’s Sixth Amendment right to confront Rudy
    was harmless beyond a reasonable doubt.
    Mr. Terrell also claims that he was a drug dealer, but
    not a member of the charged conspiracy. He contends
    that the evidence at trial showed that he was not a
    member of the Mafia Insanes gang, but rather another
    gang called the Cicero Insane Vice Lords. Mr. Terrell
    emphasizes that he did not pay street taxes to Mr. Martin.
    He concedes that Donnell Simmons told the jury how
    Mr. Terrell had supplied certain Mafia Insanes dealers
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265        59
    with drugs. However, Mr. Terrell contends that the
    Simmons testimony could not have been believed with-
    out corroboration from Rudy. He also contends that
    merely supplying drugs to the Mafia Insanes gang
    did not make him part of the charged conspiracy.
    The Government points out that five witnesses testi-
    fied about Mr. Terrell’s involvement in the charged con-
    spiracy and that the jury heard wiretap recordings
    of telephone calls between Mr. Terrell and other co-con-
    spirators. It claims that these calls revealed that
    Mr. Simmons, Mr. Terrell and another co-conspirator,
    Mario Taylor, cooperated to avoid law enforcement
    detection of their narcotics distribution efforts. It points
    out that Christopher Clark, Mr. Terrell’s confederate,
    testified that Mr. Terrell and Clark fronted large amounts
    of narcotics to Mr. Simmons, Mr. Taylor and other de-
    fendants charged in the conspiracy. The men used
    code words in their dealings to avoid law enforcement
    detection. Mr. Terrell personally knew that Mr. Simmons
    was a high-ranking member of the Mafia Insanes
    drug distribution network, and, thus, Mr. Terrell clearly
    knew or intended that his sales would further the
    overall narcotics distribution scheme.
    After a thorough examination of the record, we are
    convinced that Rudy’s testimony contributed little, if
    any, new information for the jury’s consideration and
    that its corroborative value to the Government’s
    overall effort to convict Mr. Terrell was, at best, minimal.
    We are convinced beyond a reasonable doubt that the
    Confrontation Clause error was harmless.
    60       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    C. Jury Instructions Challenge
    1.
    Mr. Terrell separately challenges the district court’s
    refusal to give the jury a multiple conspiracies instruc-
    tion. As we have noted earlier, “Mr. Terrell’s defense
    theory was that although he may have dealt drugs per-
    sonally, he was involved in an entirely different con-
    spiracy than the conspiracy charged by the government
    in Count One of the Indictment.” Terrell Appellant’s Br. 5.
    The crux of Mr. Terrell’s position is that, although
    he conspired to distribute narcotics with his associate,
    Christopher Clark, he never conspired with the larger
    conspiracy charged in the indictment. He contends that
    his sales to Mr. Simmons and Mr. Taylor reveal merely
    a buyer-seller relationship. During closing argument,
    Mr. Terrell’s defense counsel emphasized the following
    facts in his attempt to show that Mr. Terrell had joined
    a conspiracy with Clark, but not with Mr. Simmons and
    the other Mafia Insanes co-conspirators: (1) that Mr. Terrell
    was not a member of the Mafia Insanes gang; (2) that
    Mr. Terrell did not pay street taxes to the Mafia Insanes;
    (3) that Mr. Terrell actually competed for customers
    with the Mafia Insanes; and (4) that Mr. Terrell’s goal
    was exclusively to make money for himself.
    Mr. Terrell’s counsel proposed that the district court
    give a multiple conspiracy jury instruction modeled on
    the Sixth Circuit Pattern Jury Instructions 3.08 and 3.09.
    See Trial Tr. at 959, Jul. 18, 2007. The Government ob-
    jected to the instructions on the ground that no
    evidence supported Mr. Terrell’s theory of multiple
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265                  61
    conspiracies. The district court noted that the pattern
    jury instructions referred to multiple defendants,
    while Mr. Terrell had been tried alone. The court also
    noted that Mr. Terrell had not modified the pattern jury
    instructions to reflect accurately his particular theory of
    multiple conspiracies. Mr. Terrell’s counsel accordingly
    submitted a revised version of the proposed multiple
    conspiracies instructions.2 9 Defense counsel then argued
    29
    Mr. Terrell’s revised proposed instruction 3.08 read as follows:
    (1) The indictment charges that the defendants were all
    members of one single conspiracy to commit the crime
    of knowingly and intentionally to possess with intent
    to distribute and to distribute controlled substances,
    namely, in excess of 5 kilograms of mixtures con-
    taining cocaine and in excess of 50 grams of mixtures
    containing cocaine base (in the form of “crack” cocaine),
    Schedule II Narcotic Drug Substances; and in excess
    of 1 kilogram of mixtures containing heroin, and
    marijuana, Schedule I controlled Substances, in viola-
    tion of Title 21, United States Code, Section 841(a)(1).
    (2) The defendant has argued that there were really
    separate conspiracies, one between Jerome Terrell and
    Christopher Clark to commit the crime of possession
    with intent to distribute cocaine and cocaine base
    and another one between the Mafia Insane Vice Lords
    to commit the crime of Possession with intent to distrib-
    ute cocaine, cocaine base, heroin and marijuana.
    (3) To convict any one of the defendant [sic] of the
    conspiracy charge, the government must convince
    you beyond a reasonable doubt that the defendant
    (continued...)
    62           Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    that the instructions were necessary because Mr. Terrell
    was part of a smaller conspiracy than the one charged in
    the indictment. See Trial Tr. at 972, Jul. 19, 2007 (“What
    has the government shown was the agreement? Was it
    this overarching agreement between [Mr. Terrell] and
    the conspiracy, which is what is necessary, of course, or
    was there a smaller conspiracy going on where there
    was agreement perhaps with Christopher Clark and
    Donnell Simmons?”).
    The district court indicated confusion about whether
    Mr. Terrell was arguing that he was innocent of joining
    the charged conspiracy or whether he admitted to
    joining the conspiracy, but only a small part of it. The
    Government also reiterated its objections to the pro-
    29
    (...continued)
    was a member of the conspiracy charged in the indict-
    ment. If the government fails to prove this, then you
    must find that defendant not guilty of the conspiracy
    charge, even if you find that he was a member of
    some other conspiracy. Proof that a defendant was a
    member of some other conspiracy is not enough to
    convict.
    (4) But proof that defendant was a member of some
    other conspiracy would not prevent you from returning
    a guilty verdict, if the government also proved that
    he was a member of the conspiracy charged in the
    indictment.
    See R.1875 at 2-3. Mr. Terrell’s proposed instruction 3.09
    was materially identical to the Sixth Circuit pattern jury
    instruction 3.09. Id. at 3-4.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265        63
    posed instructions as unsupported by the evidence. Id. at
    974. A colloquy followed between the court and counsel:
    THE COURT: Let me ask another question.
    If Mr. Terrell conspired with Mr. Clark to
    commit the crime of possession with intent to
    distribute, which is what the defendant is effec-
    tively conceding in paragraph 2, and Mr. Clark
    was a part of the conspiracy that’s charged in the
    indictment, and some of Mr. Terrell’s activities
    with Mr. Clark were also part of Mr. Clark’s ac-
    tivities with respect to the conspiracy as a
    whole, why isn’t that sufficient to establish that
    Mr. Terrell is a member of the conspiracy?
    [THE GOVERNMENT]: We think it is.
    THE COURT: Remember, one of the principles
    that is just well recognized is that the defendant
    doesn’t have to know all the members of the
    conspiracy. He doesn’t have to know what all
    the other ones were up to or when and how they
    were doing it as long as he agreed with one or
    more other members to participate in the alleged
    wrongdoing. It seems to me that that’s what
    the charge establishes here.
    [DEFENSE COUNSEL]: They have to further the
    overall cause, your Honor. They have to further
    the overall cause of the conspiracy. I think that’s
    the bottom line in any conspiracy trial. One, that
    there was a conspiracy; and, number two, that
    this person joined it with the intent of furthering
    64        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    that conspiracy. So you need an agreement, and
    that’s what the courts have been saying is that
    you have to look at the agreement.
    Was he in agreement with this entire conspiracy,
    or was he in agreement with Christopher Clark?
    Now, if he was in agreement with Christopher
    Clark, what this instruction is telling the jury is
    that, look, that’s not enough. He just has an agree-
    ment with Christopher Clark. It doesn’t mean he
    has an agreement with everybody else in this
    conspiracy.
    THE COURT: All right. Here is an instruction to
    which there was no objection: “The government
    need not prove that the defendant knew all of the
    coconspirators or knew each detail of the conspir-
    acy or that the defendant played more than a
    minor role. The defendant need not have partici-
    pated in all of the events of the charged con-
    spiracy to be a member of that conspiracy.”
    [THE GOVERNMENT]: Judge, if I can just say one
    thing.
    I think you have hit the nail on the head. If the
    government proves that the two individuals,
    Mr. Clark and Mr. Terrell, who are both men-
    tioned in paragraph 1 of the indictment, agreed
    with each other, I think that’s the end of the
    story. I think that based on that, this instruction
    is a misstatement of the law.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         65
    We think we have proved more than that mini-
    mum agreement between Mr. Terrell and Mr.
    Clark. We think we have shown several agree-
    ments. This is a very large conspiracy by num-
    erous factions of the Vice Lords, and there is a
    great deal of evidence in this case that there were
    agreements beyond the Clark/Terrell agreement.
    But the Clark/Terrell agreement does the trick as
    far as the government is concerned as far as just
    the existence of the conspiracy. It may not show
    or it may be more doubtful whether it shows the
    quantities and all the things that I think we can
    prove with all the other evidence we have pre-
    sented. But as far as establishing a conspiracy,
    I think this instruction that’s offered, this Sixth
    Circuit instruction, confuses the issue.
    THE COURT: I am going to sustain the govern-
    ment’s objection to the multiple conspiracies
    instruction.
    Id. at 975-78.
    Mr. Terrell next moved for the inclusion of the
    Seventh Circuit pattern buyer-seller relationship instruc-
    tion, which the district court agreed was appropriate.
    Id. at 980-81.
    The jury convicted Mr. Terrell on the conspiracy
    count, among others. In his Rule 33 post-trial motion,
    Mr. Terrell contended that the district court had erred
    by refusing his proposed multiple conspiracies instruc-
    tions. The district court denied the motion, explaining:
    66        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Terrell effectively concedes that the evidence was
    sufficient to establish that he was guilty of con-
    spiring with others to distribute narcotics: The
    government presented the testimony of Donnell
    Simmons, the supervisor of a “drug spot” to
    whom Terrell supplied quantities of powder and
    crack cocaine. Christopher Clark, who served as a
    courier for the drugs that Terrell supplied and
    cash that Simmons returned, also testified. The
    evidence included recorded conversations in
    which Clark told Simmons that he was waiting
    for a cocaine supply from Terrell, as well as a call
    in which Simmons advised Terrell about a device
    that would enable Terrell to determine if “some-
    body’s wearing a wire,” and another one in
    which Simmons warned Terrell about police
    surveillance over Terrell’s own drug spot. Terrell
    and his courier, Clark, also interacted with
    Mario Taylor and with three drug sellers
    working under Mario Taylor’s supervision, using
    shorthand expressions in a manner that amply
    reflects Terrell, Clark, and Mario Taylor’s shared
    understanding of the practice of providing or
    obtaining particular quantities of cocaine for
    cash. At Defendant’s request, the court did give
    the jury a “buyer-seller” instruction. He now
    contends that, had the court also given a “multiple
    conspiracies” instruction, the jury would not
    have held him accountable for such a large quan-
    tity of drugs. But this argument ignores the evi-
    dence that Terrell himself was involved in traf-
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265           67
    ficking prodigiously large quantities of cocaine;
    that he had a standardized way of doing busi-
    ness with others over a substantial time period;
    and that he maintained a financial interest in
    the drug business conducted by others.
    R.2130. Mr. Terrell appeals the district court’s ruling.
    2.
    Mr. Terrell contends that the district court denied his
    right to a fair trial by refusing the proposed multiple
    conspiracies instruction. He argues that the trial evi-
    dence showed that “[t]he goal of the conspiracy charged
    by the government in Count One was the financial better-
    ment of Mr. Martin’s drug operation,” but that “[t]he goal
    of [the conspiracy Mr. Terrell admitted to participating
    in with Mr. Clark] was the betterment of Mr. Terrell’s
    financial interests and the interests of those working with
    him.” Terrell Appellant’s Br. 10; see also Terrell Reply Br. 4.
    He emphasizes that his proposed instructions “did not
    instruct the jury that it should acquit Mr. Terrell if he
    conspired with a subset of the charged conspiracy,” and
    he concedes that such an instruction would have been
    erroneous as a matter of law. Terrell Reply Br. 1. He
    contends that sufficient evidence supported his theory
    of multiple conspiracies. See Terrell Appellant’s Br. at 10-
    11 (suggesting that he was not a member of the Mafia
    Insanes street gang, that he did not pay street taxes to
    the leadership of that gang and that he was in a con-
    spiracy that actually competed with the Mafia Insanes).
    He admits that the evidence showed that he sold drugs
    68        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    to members of the charged conspiracy, but maintains
    that those sales were not in furtherance of the conspiracy,
    but rather were typical of a buyer-seller relationship. Id.
    3.
    We generally review for abuse of discretion a district
    court’s refusal to provide a requested jury instruction.
    See United States v. Campos, 
    541 F.3d 735
    , 744 (7th Cir.
    2008). However, “[w]e review the district court’s refusal
    to instruct the jury on a theory of defense de novo.”
    United States v. Jenkins, 
    419 F.3d 614
    , 618 (7th Cir. 2005).
    “A defendant is entitled to an instruction on his theory
    of defense only if ‘(1) the instruction provides a correct
    statement of the law; (2) the theory of defense is sup-
    ported by the evidence; (3) the theory of the defense
    is not part of the government’s charge; and (4) the
    failure to include the instruction would deprive the
    defendant of a fair trial.’ ” Campos, 
    541 F.3d at 744
     (quoting
    United States v. Millet, 
    510 F.3d 668
    , 675 (7th Cir. 2007)).
    “If the instructions treated the conspiracy issue fairly
    and adequately, we will not disturb them.” United States
    v. Severson, 
    3 F.3d 1005
    , 1011 (7th Cir. 1993).
    To be guilty of conspiring, one must agree with
    another person, with the necessary criminal intent, to
    achieve a certain criminal objective. See United States v.
    Thornton, 
    197 F.3d 241
    , 254 (7th Cir. 1999). “The crime of
    conspiracy focuses on agreements, not groups.” United
    States v. Townsend, 
    924 F.2d 1385
    , 1389 (7th Cir. 1991).
    Thus, the Government must prove that “the defendant
    joined the agreement alleged, not the group.” 
    Id.
     “The
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265              69
    agreement is all-important in conspiracy, for one must
    look to the nature of the agreement to decide several
    critical issues, such as whether the requisite mental
    state is also present, whether the requisite plurality is
    present, and whether there is more than one conspir-
    acy. As courts have so often said, the agreement is the
    essence or gist of the crime of conspiracy.” 2 Wayne R.
    LaFave, Substantive Criminal Law § 12.2(a) (2d ed. 2010)
    (internal quotation marks and footnotes omitted); see
    also United States v. Varelli, 
    407 F.2d 735
    , 742 (7th Cir. 1969)
    (“In essence, the question is what is the nature of the
    agreement.”). “Even when it is clear that every defendant
    is a conspirator, it may be extremely important to deter-
    mine precisely what the object dimension and party
    dimension of the agreement are, for that in turn will
    decide the critical question of whether more than one
    conspiracy exists.” Lafave, Substantive Criminal Law,
    supra, § 12.3(b). “Multiple conspiracies exist when there
    are separate agreements to effectuate distinct purposes.”
    Thornton, 
    197 F.3d at 254
    .
    Here, Mr. Terrell was tried alone.3 0 The jury instructions
    30
    Determining whether multiple conspiracies existed is par-
    ticularly important when several defendants are tried together.
    If the defendants joined multiple and distinct conspiracies,
    trying the defendants jointly risks allowing the jury to trans-
    fer “guilt from one to another across the line separating
    [the] conspiracies, subconsciously or otherwise.” Kotteakos v.
    United States, 
    328 U.S. 750
    , 774 (1946). In such cases, a multiple
    conspiracies instruction may be warranted. 
    Id. at 769-72
    ; see
    also United States v. Schmucker-Bula, 
    609 F.2d 399
    , 403 (7th Cir.
    (continued...)
    70        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    issued by the district court explained adequately that
    Mr. Terrell should be acquitted if the evidence failed
    30
    (...continued)
    1980) (“It is true, as the defendant argues, that courts should
    be vigilant against the transfer of guilt ‘from one to another
    across the line separating conspiracies . . . .’ Kotteakos v.
    United States, 
    328 U.S. 750
    , 774 (1946). It is also true, how-
    ever, that the existence of multiple conspiracies is a ques-
    tion of fact, and the role of the court is generally limited to in-
    structing the jury when the possibility of a variance between
    the evidence and the conspiracy charged in the indictment
    arises. See United States v. Papia, 
    560 F.2d 827
    , 838 (7th Cir.
    1977); United States v. Varelli, 
    407 F.2d 735
    , 746 (7th Cir. 1969).
    The trial court properly instructed the jury that proof of sev-
    eral conspiracies is insufficient to permit conviction unless
    one of the conspiracies proved is the one charged in the in-
    dictment.” (parallel citations omitted)).
    This problem usually is not present when a defendant is
    tried alone. In such a case, a multiple conspiracies instruction
    well may be unnecessary. See United States v. Anguiano, 
    873 F.2d 1314
    , 1318 (9th Cir. 1989) (“[A] multiple conspiracies
    instruction is generally designed for trials involving multiple
    defendants engaged in multiple conspiracies, not for trials of
    lone defendants who are worried that the jury may not
    agree upon the same set of facts.”); see also United States v.
    Richardson, 
    532 F.3d 1279
    , 1290-91 (11th Cir. 2008); United States
    v. Corey, 
    566 F.2d 429
    , 431 n.3 (2d Cir. 1977). Therefore, as long
    as the district court instructs the jury on the nature of the
    conspiracy charge, emphasizing that the Government must
    prove that the defendant intentionally agreed to advance the
    aim of the conspiracy, there is usually no need for a
    multiple conspiracies instruction when a defendant is tried
    alone.
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265         71
    to establish the existence of the charged conspiracy or
    that Mr. Terrell did not agree to join it. Furthermore, the
    evidence in this case did not warrant the issuance of
    a multiple conspiracies instruction. A multiple con-
    spiracies instruction is unnecessary when the evidence
    reveals the existence of only one conspiracy. See United
    States v. Longstreet, 
    567 F.3d 911
    , 921 (7th Cir. 2009);
    Jenkins, 
    419 F.3d at 618
    ; see also Thornton, 
    197 F.3d at 255
    ;
    United States v. Mims, 
    92 F.3d 461
    , 467-68 (7th Cir.), reh’g
    granted on other grounds 
    101 F.3d 494
     (7th Cir. 1996);
    United States v. Shorter, 
    54 F.3d 1248
    , 1256 (7th Cir. 1995).
    The nonexistence of multiple conspiracies may be so
    obvious that the jury need not be instructed on that
    issue. See Severson, 
    3 F.3d at 1010
    .
    Here, upon examination of the record, we believe
    the evidence adduced during Mr. Terrell’s trial re-
    vealed only one, interdependent conspiracy to distribute
    narcotics. We emphasize that the purpose of the con-
    spiracy charged in Count One of the indictment
    was simply to distribute narcotics. Mr. Terrell fails to
    articulate a different or distinct purpose for the con-
    spiracy he admits to have joined with Christopher
    Clark. Mr. Terrell’s characterization of an alternative
    conspiracy, consisting of an agreement with Clark to
    further Mr. Terrell’s financial interests, as opposed to
    the financial interests of the Mafia Insanes gang, is
    nothing more than a description of a subset of the con-
    spiracy charged in the indictment. “One can join a con-
    spiracy to make money, even though others join it for
    different reasons. The question is whether the parties
    have agreed to advance a common goal.” United States
    72        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    v. Duff, 
    76 F.3d 122
    , 127 (7th Cir. 1996).3 1 Although
    we have trouble conceiving of a reason motivating the
    co-conspirators in this case to join the conspiracy, other
    than to advance their individual financial interests,
    that issue is beside the point; each co-conspirator’s finan-
    cial motivation for joining the conspiracy is essentially
    irrelevant.
    What is clear, and of paramount relevance, is that
    each co-conspirator agreed to advance the conspiracy’s
    goal of distributing narcotics. The evidence revealed that
    Mr. Terrell fronted wholesale quantities of narcotics to
    the members of the conspiracy and took steps, such as
    cooperating with Mr. Simmons to avoid police detec-
    tion, to further the conspiracy’s objectives. Because
    Mr. Terrell and Christopher Clark were both charged
    as co-conspirators in Count One of the indictment,
    Mr. Terrell’s concession that he conspired to distribute
    narcotics with Clark, along with the evidence that
    Mr. Terrell fronted narcotics to other co-conspirators
    with knowledge that the narcotics would be distributed,
    31
    The facts that Mr. Terrell did not pay street taxes to and was
    not a member of the Mafia Insanes does not establish the
    existence of multiple conspiracies. The crucial fact is that all
    the co-conspirators agreed to distribute narcotics in the west
    side of Chicago during the relevant time period.
    Of course, isolated instances of cooperation between com-
    peting drug distribution networks may not support the ex-
    istence of one, overarching conspiracy. Cf. United States v.
    Townsend, 
    924 F.2d 1385
    , 1393 (7th Cir. 1991) (discussing
    United States v. Fiorito, 
    499 F.2d 106
    , 109 (7th Cir. 1974)).
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265       73
    essentially precludes a theory of multiple conspiracies.
    The Government “may elect to proceed on a subset
    of the allegations in the indictment, proving a conspiracy
    smaller than the one alleged, so long as the subset is
    also illegal.” United States v. Wilson, 
    134 F.3d 855
    , 865
    (7th Cir. 1998) (internal quotation marks and citation
    omitted); see also Campos, 
    541 F.3d at 745
    ; United States
    v. Payne, 
    226 F.3d 792
    , 795 (7th Cir. 2000). Although
    there was some evidence that Mr. Terrell competed
    with his co-conspirators for customers from time-to-
    time, there was other evidence that he frequently co-
    operated with members of the conspiracy and agreed to
    further the conspiracy’s objective. The jury rejected
    Mr. Terrell’s buyer-seller theory and based its verdict
    on the substantial evidence showing that Mr. Terrell
    agreed to join the conspiracy to distribute narcotics. Cf.
    United States v. Sir Kue Chin, 
    534 F.2d 1032
    , 1035 (2d Cir.
    1976) (“The essence of the crime is an agreement, and
    there is no more reason to say that a supplier of narcotics
    is necessarily engaged in two conspiracies because he
    has two sources of supply than there would be because
    he had two purchasers.”).
    Finally, we note that Mr. Terrell’s buyer-seller theory
    was valid and an essential component of his defense.
    That theory depended on a characterization of the evi-
    dence showing that Mr. Terrell never agreed to join
    the conspiracy in the first place. The district court’s
    instructions on that subject were satisfactory.
    Mr. Terrell was not entitled to the multiple conspiracies
    instruction because the theory of defense was not sup-
    74        Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    ported by the evidence. The theory of the defense was
    essentially a subset of the Government’s charge and the
    failure to include the instruction did not deprive
    Mr. Terrell of a fair trial. The instruction given by the
    district court put the case before the jury in a straight-
    forward and comprehensive manner.
    D.
    Sentencing Enhancement Challenge
    Mr. Bell also challenges the inclusion of the U.S.S.G.
    § 2D1.1(b)(1) enhancement in the district court’s guide-
    lines calculation. That enhancement applies when the
    defendant possessed a dangerous weapon during the
    course of the commission of the drug offense.
    The government bears the burden of first proving
    by a preponderance of the evidence that the de-
    fendant possessed the weapon. The defendant
    need not have actual possession of the weapon;
    constructive possession is sufficient. If the gov-
    ernment carries its burden, then the defendant
    must show that it was clearly improbable that
    the weapon was connected to the drug offense.
    United States v. Are, 
    590 F.3d 499
    , 526 (7th Cir. 2009)
    (internal quotation marks and citations omitted). Co-con-
    spirators’ foreseeable possession of dangerous weap-
    ons may be attributable to a defendant so as to trigger
    application of the enhancement. See United States v. Emer-
    son, 
    501 F.3d 804
    , 815 (7th Cir. 2007). We review factual
    findings under U.S.S.G. § 2D1.1(b)(1) for clear error. See
    Are, 
    590 F.3d at 526
    .
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265       75
    During Mr. Bell’s sentencing hearing, the Government
    argued for application of the enhancement because fire-
    arms ammunition and drugs were recovered from
    Mr. Bell’s residence at the time of his arrest and because,
    in telephone calls between Mr. Bell and co-conspirators
    recorded during the course of the conspiracy, Mr. Bell
    asked to borrow a “thumper” for protection and bragged
    about carrying a “thumper” to avoid capture by the
    police. See R.1902, Ex. A. A co-conspirator testified that
    a “thumper” referred to a pistol. See Trial Tr. at 475-76,
    Sept. 6, 2006. The district court ruled that the Govern-
    ment had met its burden because the circumstantial
    evidence supported a finding that Mr. Bell had pos-
    sessed a dangerous weapon during the course of the
    conspiracy. The district court also noted that countless
    pieces of evidence adduced at trial supported the infer-
    ence that co-conspirators’ possession of dangerous weap-
    ons was foreseeable. The district court discounted co-
    conspirator testimony to the effect that he never gave
    Mr. Bell a firearm.
    Mr. Bell contends that the district court’s factual
    finding was erroneous. He submits that the district
    court should have believed the co-conspirator’s testi-
    mony and that the recorded telephone calls were too
    ambiguous to have supported the finding. We disagree.
    The finding clearly was supported by the evidence. The
    district court weighed appropriately the evidence and
    explained sufficiently its finding. The Government met
    its burden and the enhancement was applied correctly
    in Mr. Bell’s guidelines calculation.
    76       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    E.
    Other Sentencing Challenges
    Messrs. Martin, Bell, Taylor and Braboy raise a host
    of additional challenges to their sentences. Messrs. Taylor
    and Braboy contend that the district court erred by
    failing to consider and articulate its consideration of
    certain 
    18 U.S.C. § 3553
    (a) factors when it imposed their
    sentences. We review sentences for reasonableness
    under an abuse-of-discretion standard. See Gall v. United
    States, 
    552 U.S. 38
    , 51 (2007). Sentences within an appro-
    priately calculated guidelines range are presumptively
    reasonable. Id.; see also United States v. Wallace, 
    531 F.3d 504
    , 507 (7th Cir. 2008). When considering the 
    18 U.S.C. § 3553
    (a) factors, the district court need not “write
    a comprehensive essay applying the full panoply of
    penological theories and considerations, which is to
    say everything invoked or evoked by section 3553(a).”
    United States v. Dean, 
    414 F.3d 725
    , 729 (7th Cir. 2005); see
    also United States v. Jumah, 
    599 F.3d 799
    , 813-14 (7th Cir.
    2010); United States v. Laufle, 
    433 F.3d 981
    , 987 (7th Cir.
    2006).
    Messrs. Taylor and Braboy contend that the district
    court failed to take into account their history and charac-
    teristics, specifically their troubled childhoods and their
    ages at the time of sentencing. However, during the
    sentencing hearing, the district court stated that it
    had considered Mr. Taylor’s “entire record” and noted
    that Mr. Taylor had “made a significant change in [his]
    life,” reflecting that the district court had compared
    Mr. Taylor’s lifestyle and personal characteristics exhib-
    Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265      77
    ited before his arrest with his post-arrest conduct. Tr.
    at 26, Dec. 10, 2007. During Mr. Braboy’s sentencing
    hearing, the district court referenced several specific
    arguments asserted in his sentencing memorandum,
    including Mr. Braboy’s newfound maturity, and stated
    that “I know that given the family background, . . . the
    temptation to just get involved in criminal conduct is
    enormous.” Tr. at 41-42, Dec. 4, 2007. These statements
    reveal that the district court gave due consideration to
    the § 3553(a) factors raised by the defendants. The de-
    fendants concede that the district court appropriately
    calculated their guidelines ranges. The within-guidelines
    sentences that the district court imposed were reasonable.
    Next, Messrs. Martin and Bell contend that the district
    court erred by not considering whether the sentencing
    disparity between crack and powder cocaine yields a
    sentence greater than necessary to achieve 
    18 U.S.C. § 3553
    (a)’s purpose. Kimbrough v. United States, 
    552 U.S. 85
     (2007). The Government agrees that a limited remand
    to consider this issue is appropriate. Accordingly, we
    order a limited remand so that the district court may
    follow the procedures described in United States v.
    Taylor, 
    520 F.3d 746
    , 748-49 (7th Cir. 2008), to address
    the effect of both the 2007 Amendment to U.S.S.G. § 2D1.1
    and Kimbrough v. United States, 
    552 U.S. 85
     (2007), on
    Messrs. Martin’s and Bell’s sentences. After resolving
    any motion for a reduced sentence under 
    18 U.S.C. § 3582
    (c)(2) based on the Amendment, the court should
    indicate whether it is inclined to reduce further
    78       Nos. 07-2272, 07-3893, 07-3940, 07-4010 & 08-3265
    Messrs. Martin’s or Bell’s sentences under Kimbrough.3 2
    Additionally, although Messrs. Braboy and Taylor did not
    raise the Kimbrough issue in their appellate arguments,
    we note that they were sentenced prior to the issuance
    of Kimbrough, and, thus, are entitled to a remand pursuant
    to the procedures we described in United States v.
    Taylor, 
    520 F.3d 746
    , 748-49 (7th Cir. 2008). Mr. Terrell
    was sentenced after the enactment of the 2007 Amend-
    ment and Kimbrough, and, thus, he could have raised
    those issues before the district court if the court had not
    addressed adequately those issues. Accordingly, the
    record does not support a remand for resentencing for
    Mr. Terrell.
    Conclusion
    For the foregoing reasons, we affirm the district court’s
    pretrial and trial rulings. We order limited remands for
    reconsideration of Messrs. Martin’s, Bell’s, Braboy’s and
    Taylor’s sentences.
    A FFIRMED in part;
    R EMANDED in part
    32
    We already have severed Mr. Simmons’s appeal, No. 07-2039
    and Jermaine Banks’s appeal, No. 07-1444, and remanded
    with identical instructions on this issue.
    8-24-10