                              In the

United States Court of Appeals
                 For the Seventh Circuit

No. 07-3348

U NITED S TATES OF A MERICA,
                                                  Plaintiff-Appellant,
                                  v.

E DDIE B ANKS,
                                                 Defendant-Appellee.


             Appeal from the United States District Court
        for the Northern District of Illinois, Eastern Division.
          No. 05 CR 848—James F. Holderman, Chief Judge.



      A RGUED M AY 28, 2008—D ECIDED O CTOBER 9, 2008




  Before E ASTERBROOK, Chief Judge, and R IPPLE and W OOD ,
Circuit Judges.
  W OOD , Circuit Judge. This case illustrates the critical
role that the standard of appellate review can, and must,
play in our judicial system. As we explained in United
States v. Williams, 81 F.3d 1434 (7th Cir. 1996), “[it] is
difficult for nonlawyers to understand or accept . . . that
because the question whether to grant a new trial is
committed to the discretion of the district judge, as the
2                                               No. 07-3348

defendants rightly concede, United States v. Knox, 68 F.3d
990, 1000 (7th Cir. 1995); United States v. Maloney, 71 F.3d
645, 654 (7th Cir. 1995), it is possible for two judges,
confronted with the identical record, to come to opposite
conclusions and for the appellate court to affirm both. That
possibility is implicit in the concept of a discretionary
judgment.” 81 F.3d at 1437 (emphasis removed). In Wil-
liams, we found that one district judge did not abuse
his discretion when he refused to grant a new trial based
on the government’s use of perjured testimony, even
though we had found that a different district judge who
was trying other defendants involved in the very same
conspiracy also did not abuse his discretion when he
did grant a new trial based on exactly the same perjured
testimony. See United States v. Boyd, 55 F.3d 239 (7th Cir.
1995).
  In the case now before us, defendant Eddie Banks was
charged in a multi-defendant indictment with four drug-
related counts (counts 1, 10, 30, and 31). A jury convicted
Banks on all four counts and made a special finding for
counts 1 and 10 that the conspiracy and distribution
offenses involved at least 500 grams but less than 5 kilo-
grams of cocaine. Based on information that came to
light after the jury delivered its verdict, Banks moved for
a new trial. The district court granted a new trial on
count 10 and a new trial on the drug type and quantity
applicable to counts 1 and 10. The Government has ap-
pealed from those orders. Bearing in mind the fact that,
just as in Williams and Boyd, we are reviewing only for
abuse of discretion, we affirm.
No. 07-3348                                               3

                             I
  A great deal of evidence was presented against Banks
in his drug trial. The Government collected numerous
recorded telephone conversations between Banks and
others relating to cocaine deals. Informant and drug dealer
Clarence Whalum testified that he sold cocaine to Banks
every two or three weeks in quantities ranging from over
two ounces to one kilogram, and that he participated in
a controlled sale of a kilogram of cocaine to Banks. There
was also police testimony describing surveillance of Banks
immediately after the purchase from Whalum. Officers
pulled Banks over for a traffic infraction, seized the
package that Banks had hastily stashed in his pants,
released him to protect the integrity of their investiga-
tion into the drug conspiracy, and then arrested him on a
later occasion. Finally, at the center of this appeal is the
expert testimony of Drug Enforcement Administration
(DEA) forensic chemist Theresa Browning, who testified
that she had tested the material in the package seized by
police and found that it was 999.1 grams of cocaine hydro-
chloride. The theory of the defense was that Banks was
not the person who was pulled over by the police in
possession of the package that later tested positive for
cocaine.
  After the jury returned a verdict of guilty on all four
counts, the prosecution and defense learned for the first
time that Browning was under investigation at the time
of trial for professional misconduct, described further
below. Banks moved for a new trial based on the Govern-
ment’s failure to disclose this impeaching information. The
4                                             No. 07-3348

district court concluded that a new trial was necessary
only on count 10 and the special finding of drug type and
quantity relating to counts 1 and 10, and it entered an
appropriate order, from which the Government has
appealed. See 18 U.S.C. § 3731, ¶ 1. (Banks’s convictions
under counts 30 and 31 for using a telephone to facilitate
a violation of the drug laws are not affected by the
district court’s order.)
   Information brought out during a post-trial hearing
revealed that at the time she testified, Browning was
fighting off accusations about misuse, or possibly even
fraud, in connection with the use of her government-
issued credit card. As a federal employee, Browning was
entitled to have the card for purposes of covering
expenses related to her government employment—primar-
ily travel expenses. Normally, before the due date for
payment on the credit card, the Government would deposit
directly into her bank account money to cover the ex-
penses. She was required to use these funds to pay the
credit card bill, and timely payment was required. In
March 2006, however, Browning used the deposited
funds to pay for personal expenses and then had insuffi-
cient funds available when her government credit card
bill came due. This constituted misappropriation of those
funds. Browning waited until her next paycheck came
and then paid off the card, but her payment was one
week late. She had not requested an extension and did not
self-report this violation.
  When the misconduct was discovered, Browning feared
that she would lose her job and asked her supervisor to
No. 07-3348                                                  5

“keep the consequences at the laboratory level”—in other
words, not to let the higher-ups at DEA know about her
misstep. The supervisor did not honor this request, and
instead reported Browning’s violation to the DEA Office
of Professional Responsibility (OPR), which investigated
the matter. OPR interviewed Browning approximately
four months prior to her testimony in Banks’s trial, and
Browning heard nothing further about the status of the
investigation for a long time. She still knew nothing at the
time of her testimony at Banks’s trial, but she heard from
OPR a few days after the trial was over. In the end, the
only professional consequence she suffered from her
misconduct was the agency’s issuance of a letter of
caution warning her to make future payments in a timely
manner. The letter was issued on October 4, but Browning
did not receive it until October 20, after testifying
against Banks on October 17, 2006. The prosecutors did not
know anything about Browning’s problem until after the
trial.


                              II
  Under Brady v. Maryland, 373 U.S. 83 (1963), the Govern-
ment has a duty to disclose evidence favorable to the
defendant, whether the evidence is exculpatory or tends
to impeach a Government witness. Strickler v. Greene,
527 U.S. 263, 280 (1999). Nonetheless, a violation of this
duty, whether intentional or inadvertent, entitles the
defendant to a new trial only if the failure to disclose the
evidence resulted in denial of a fair trial. Id. at 281-82. The
latter condition is satisfied only when the suppressed
6                                                No. 07-3348

evidence is material, meaning when there is “a reasonable
probability that, had the evidence been disclosed to the
defense, the result of the proceeding would have been
different.” United States v. Bagley, 473 U.S. 667, 682 (1985).
  The only point of dispute in this case is whether the
undisclosed information was “material” in the Bagley
sense of the term. The Government has not argued
that Browning’s testimony related only to the underlying
question whether the substance was really cocaine, and, on
that point, the defense was just as well positioned to test
it as the prosecution was. If the evidence about
Browning’s legal problems was material, then Banks was
entitled to a new trial. The district court held that the
fact that Browning was under investigation by her gov-
ernment employer at the time she tendered testimony
favorable to the Government in Banks’s criminal case
was material impeachment evidence with respect to the
guilt phase on count 10, and material with respect to the
sentencing factors of drug type and quantity for counts 1
and 10.
  At oral argument, a member of the panel raised the
question whether the Brady rule should be invoked to
grant a new trial for non-disclosure of this type of im-
peachment evidence. The question is first whether we
should be focusing not on Browning but on the topic of her
testimony—the nature of the substance—and second,
whether the law draws any distinction between a
witness who may be lying about a verifiable subject and
a witness who may be lying about a non-verifiable
subject (such as a visual observation). Under the theory
No. 07-3348                                                  7

(once again, not presented by the Government) that the
only question is whether the substance in the package
was really cocaine, one might ask what a new trial would
accomplish. If Banks had impeached Browning with this
evidence, then the Government now asserts that it would
simply have put a different expert on the stand (presum-
ably one whose work could not be impeached, though
without a crystal ball, it is hard to be confident about that).
The Government did not proffer evidence to this court
that later tests have confirmed Browning’s chemical
findings. It has only alleged that Browning was the
second chemist to test the material and determine it to be
cocaine, but it has not provided either the name, the date,
the laboratory, or any other information about this sup-
posed earlier test. Indeed, it supports this assertion only
by pointing to Browning’s testimony that she was the
second chemist to make such a finding.
  If we are to acknowledge the possibility that Browning’s
conflict of interest led her to falsify her own chemical
analysis and commit perjury, we cannot rely on her own
testimony that her findings were corroborative of another
chemist’s. We note as well that reasonable people could
disagree about the effect of Browning’s troubles on her
testimony. Some might think that her credit-card misuse
might have prompted her to be especially careful when
she tested the substance, so that she could demonstrate
what a valuable employee she is. On that theory, the
missing evidence would not even have impeached her.
Others might think that her employment problems
might have caused her to rush the job and to say
whatever she thought the prosecutor wanted to hear,
8                                                No. 07-3348

counting on the fact that it probably was cocaine anyway.
But see United States v. Salgado, 519 F.3d 411, 412 (7th Cir.
2008) (dealer could not find genuine cocaine and was
planning to cheat buyer). The fact that there are at least
two plausible explanations indicates that the choice
between them was one for the district court to make.
  We therefore save for another day any more thorough
exploration of the theory that, in evaluating motions for
new trial based on evidentiary problems, we must focus on
alternative ways that the objecting party might have
proved the point on which the witness was going to
testify, and that there is a distinction embedded in the
law between verifiable and nonverifiable observations.
Perhaps such a distinction would make sense. Perhaps,
every time either the Government or a defendant wants
a new trial based on a problem with an expert witness,
there should first be a hearing to see if an alternate expert
might have been produced by the affected side who
would have said the same thing as the tainted expert.
On these facts, it may have been better if the district court
had held such a hearing. But to acknowledge that is not
to say that the court abused its discretion by taking the
course it did. We thus proceed to consider the Govern-
ment’s appeal on the basis of the facts and arguments
that were presented to the district court and briefed here.


                             III
   In its effort to persuade us that the district court abused
its discretion in granting the limited new trial it did, the
Government first argues that the court applied the wrong
No. 07-3348                                                9

legal standard. According to the Government, the district
court collapsed the materiality inquiry into the definition
of impeachment evidence. What the district court said
was that the impeachment evidence was material because
it was
   sufficient to cause a reasonable jury to question DEA
   Forensic Chemist Browning’s credibility and reject, if the
   jury chose to do so, her opinion as an expert due to the
   bias she was harboring as a result of a desire to mini-
   mize the punishment she was yet to receive for her
   unprofessional conduct that was the subject of the
   undisclosed DEA scrutiny at the time of her testing
   Government Exhibit 4-C and her testimony at the trial.
(Gov. Short App. 2) (emphasis added).
   We do not read the district court’s remarks as the
Government does. The court’s comments must be under-
stood in light of the evidence that had been introduced at
trial. Of the witnesses testifying, only Browning and drug
dealer Whalum had first-hand knowledge of the contents
of the package in question. Whalum, aside from being a
significant drug dealer and having entered into an agree-
ment with the Government in exchange for his testimony
against Banks, also used a shocking amount of drugs on a
daily basis. (The evidence showed that he had an amazing
daily consumption of one to two fifths of hard liquor, at
least two pills of ecstasy, and ten to twenty marijuana-
filled cigars.) A jury easily could have found that
Whalum’s memory and perception were compromised and
unreliable, and then rejected Browning’s testimony on
the basis of her possible bias. That would have left this
10                                            No. 07-3348

jury with no credible testimony about the nature of the
package.
  The Government counters this inference with various
witnesses who testified about “the cocaine” without
objection from the defense, even quoting defense
counsel’s reference to “the cocaine” during closing. It
points out that the nature of the package was not even at
issue in the trial—identity was the only issue. Banks, it
says, just contested the Government’s claim that the
person who was eventually arrested (himself) was the
same one who was stopped by the police after the con-
trolled sale, and from whom the package was seized. But
Banks based his strategic choice on the information
before him. Had he known about Browning’s problem,
he may have sought an independent test of the substance
in the package. (The Government may assume that the
reason Banks did not do so was because he already knew
what the outcome of such a test would be, but there is
no evidence in the record to support such a finding apart
from that of Whalum and Browning.) Even without
his own independent test, Banks would surely have used
the information about Browning to attempt to impeach
her testimony about the nature of the substance.
  The Government also points out that Browning stated
during her testimony that she was the second chemist to
test the material, and that her findings were the same
as the findings of the prior chemist. This is not helpful.
As we have already noted, the materiality analysis
requires us to suppose that the impeachment evidence
would cause the jury to find that Browning willfully
No. 07-3348                                               11

falsified test results and committed perjury by testifying
that the substance was cocaine when it was not cocaine. If
all that is true, then the jury would be further entitled not
to credit her testimony that another chemist had tested
the material and come up with the same results. Thus, this
bit of Browning’s testimony about the prior chemical test
does not save the Government from a possible failure
of credible proof regarding the nature of the package.
  The Government next argues that if Banks is allowed to
benefit from a hypothetical analysis of what his trial
strategy would have been had he known about the im-
peaching evidence, the Government should be allowed
to do likewise. The Government claims that, had it
known about the OPR investigation of Browning prior
to trial, it could easily have found another unimpeachable
chemist to test the sample and testify to its contents in
place of Browning. (For the post-trial hearing, it pro-
duced a declaration from a DEA director confirming the
availability of other chemists to conduct the test.)
  Whether the Government’s prediction is true or not, this
point does not convince us that the district court applied
the wrong legal standard to the motion for a new trial. The
court was not required to accept on faith the Govern-
ment’s assertion that its replacement chemist would have
been unimpeachable. While we hope that this is now true
of most, if not all, of the Government’s experts, experience
suggests that such an expectation might be too optimistic.
See, e.g., David Johnston & Andrew C. Revkin, Report
Finds F.B.I. Lab Slipping from Pinnacle of Crime Fighting,
N.Y. T IMES, Jan. 29, 1997, at A1. The district court was
12                                               No. 07-3348

entitled to make a discretionary finding that the opportu-
nity to undermine the credibility of the chemist that the
Government did in fact call to testify sufficed to create
a reasonable probability of a different outcome in the case.


                             IV
  Even if the district court did not apply the wrong stan-
dard, the Government argues that it still abused its dis-
cretion in finding that the impeachment evidence was
material.
  We have already discussed the Government’s arguments
that the impeachment evidence was not material because
the presence of cocaine was not at issue in the trial, and
that a supposed prior chemist had, according to Browning,
already tested the substance and found it to be cocaine. The
Government also points to other circumstantial evidence
regarding the nature of the package, such as Banks’s
consciousness of guilt at the time of the seizure, given that
he had stuffed the package down his pants, and the fact
that he paid $14,000 for the package. This evidence was
helpful to the Government’s case against Banks, but it does
not carry such irrefutable force that we can say that the
district court abused its discretion in finding that rejection
of the chemist’s expert testimony would create a reason-
able probability of a different verdict. The Government
also notes that the jury examined the package in the jury
room. While this examination may have allowed the
jurors to determine that the package weighed somewhere
in excess of 500 grams, we fail to see how a visual examina-
tion by lay—and presumptively law-abiding—jurors
No. 07-3348                                              13

would allow the jury to determine beyond a reasonable
doubt that the package contained cocaine as opposed to
some other look-alike substance.
  The Government next claims that the impeachment
evidence was not material because the potential for bias
was exceedingly weak. First, it points out the “relatively
minor” nature of Browning’s offense. This is a subjective
judgment; the district court was not required to presume
that the jury would find the offense to be so relatively
minor that they would have no reason to believe that
Browning was concerned about her job. Indeed, Browning
admitted her concern about the matter and that she had
asked her boss to minimize the repercussions. That request
was denied; the supervisor thought the problem sig-
nificant enough to report it up the chain of command to
the OPR.
  Second, the Government notes that Browning worked
for the DEA, while Banks’s case was investigated by a
separate agency, the FBI. The DEA had no interest in
whether cocaine was found in the sample or whether
Banks was convicted or acquitted. Thus, the argument
goes, Browning would not be currying favor with her
employer by falsifying her chemical tests and committing
perjury on the stand—quite the contrary. In its reply brief,
the Government explains how the exertion of pressure on
Browning to testify falsely would require a rather far-
fetched and implausible theory of inter-agency govern-
mental conspiracy. On the other hand, the relations among
government agencies and departments can be byzantine,
and the jury would not necessarily have followed the
14                                              No. 07-3348

Government’s argument. In particular, the jury might not
have bought the Government’s assertion that the two
agencies (both part of the Department of Justice, inciden-
tally) were so insulated from one another that impropriety
was impossible. Indeed, the mere fact that the Government
concedes that the DEA investigation into Browning’s
misconduct was relevant to the question of bias (as op-
posed to merely a lack of credibility) is a concession that
it is plausible that Browning felt pressure to testify favor-
ably to the Government because of her pending disciplin-
ary action. We therefore cannot say that the district court
abused its discretion in finding that cross-examination
on this issue might have had a real impact on the jury’s
willingness to rely on Browning’s testimony (and thus
an impact on the jury’s finding with respect to the
essential element of the nature of the substance in the
package).
  In summary, although acquittal may have been less likely
than conviction even if the impeachment evidence
had come to light in time, we cannot say that the district
court abused its discretion when it found that the infor-
mation about Browning was material. The court thus
did not abuse its discretion in ordering a new trial on
count 10 and on the drug type and quantity issues relevant
to counts 1 and 10. For these reasons, we A FFIRM the
judgment of the district court.
No. 07-3348                                               15

  E ASTERBROOK, Chief Judge, dissenting. To establish a
violation of the due process clause, Banks had to show that
Browning’s credit-card problem was exculpatory evidence.
Even then, a new trial is appropriate only if there is “a
reasonable probability that, had the evidence been dis-
closed to the defense, the result of the proceeding would
have been different.” United States v. Bagley, 473 U.S. 667,
682 (1985).
  The district judge never decided whether the credit-card
evidence was exculpatory. His opinion, which covers less
than two pages, asserts that the evidence was impeaching
but does not say why. The judge must have assumed that
the credit-card problem gave Browning an incentive
to ingratiate herself with the DEA by identifying the
substance as cocaine whether it was or not, and that the
defense could have used this motive to undercut her
testimony. But that is hardly the only available inference.
  Because Browning’s assertions could have been verified
or refuted by other evidence, her financial difficulties gave
her a reason to be extra careful, not a reason to commit
perjury. A chemist found to have lied about a substance’s
composition will be fired and may be prosecuted. Careless
analysis (short of perjury) will be less acceptable from
a chemist who is in hot water than from a chemist with
a spotless record. Defense counsel would have stepped
on a land mine by introducing the credit-card evidence,
only to have Browning reply “yes, because I was in trouble
for financial issues I took extra care to analyze this sam-
ple”; the prosecutor then could have elicited on re-direct
that chemists who misidentify a substance are disciplined
16                                                No. 07-3348

and reminded the jury that the defense could have had
the substance analyzed by a forensic chemist.
  My colleagues say (slip op. 8) that when “there are at
least two plausible explanations [one impeaching and the
other not] the choice between them was one for the
district court to make.” I agree with this principle. Unfortu-
nately, the district court did not make the choice. The
court simply assumed that the credit-card evidence would
have undermined rather than strengthened Browning’s
testimony. We can’t apply a deferential standard of
appellate review when the district court has not con-
fronted the competing inferences and made a reasoned
choice. See, e.g., United States v. Beasley, 809 F.2d 1273 (7th
Cir. 1987)
  If the evidence would have undermined Browning’s
analysis, a further question must be explored. What would
have happened had the prosecutor known about this
evidence and revealed it to the defense? The district court
assumed that Browning would have testified and been
impeached. But there is another possibility. The prosecutor
might have used a different chemist. Then no impeaching
evidence would have been before the jury, and the trial
would have proceeded exactly as it did. That replacement
chemist’s testimony would not have been undercut. This
is exactly what a declaration filed by the prosecutor
(Domagala Declaration at ¶6) says would have happened.
On this understanding withholding the credit-card infor-
mation did not hamper the defense. It changed the
identity of the chemist but not the substance of any testi-
mony.
No. 07-3348                                              17

  According to the majority, the district court “was not
required to accept on faith the Government’s assertion
that its replacement chemist would have been unimpeach-
able.” Slip op. 11. I agree: Never is a district judge re-
quired to accept something on faith. Once again, however,
the problem is that the district judge did not even
mention this subject. No testimony was taken; no facts
were found; no discretion was exercised.
  Nor could the district judge have rejected Domagala’s
submission. There is no contrary evidence. A judge cannot
preemptively disbelieve statements in an affidavit. At the
post-trial hearing when Browning testified about her
financial troubles, the district judge could have
demanded that the prosecutor produce Domagala or
other proof about what could have been done to replace
Browning. After entertaining evidence from both sides,
the judge could have made findings of fact. But that was
not done.
  Everything I have said so far rests on arguments pre-
sented to the district court and reiterated in the prosecu-
tor’s appellate brief. There are deeper problems with the
district court’s approach, however. Perhaps the prosecutor
thought it unnecessary to discuss them, so clear are the
errors I have mentioned. But they are still worth attention,
because they put the issues in perspective.
  The premise of Bagley, which extended Brady v. Maryland,
373 U.S. 83 (1963), from primary exculpatory evidence
to material that could be used to impeach a witness, is that
a witness’s credibility can be vital to the strength of the
prosecution’s case. That will be so when the testimony
18                                              No. 07-3348

is not verifiable (the witness testifies to something seen or
heard, for example). It is not so when the witness’s conten-
tions can be checked by a third party. If, for example, a
witness testifies that a particular document contains
particular language, the best way to find the truth is to
look at the document, not to inquire whether the
witness has a felony conviction or is in financial trouble or
has told a contradictory story to someone else.
  Everything that Browning said could have been checked.
The question at hand was whether the seized substance is
cocaine, not whether Browning had analyzed that sub-
stance correctly (or was telling the truth about her own
analysis). Conviction (or acquittal) depends on what the
substance actually is. Cf. United States v. Moon, 512 F.3d
359 (7th Cir. 2008) (lab results are not “testimonial” under
the confrontation clause).
  Brady applies only to evidence that is known to the
government but not the defense. The seized substance,
however, was available to the defense. The jury found that
Banks was the person from whom the substance had
been seized (that conclusion, which is essential to the
verdict, is not undermined by any problem in Browning’s
testimony), and Banks himself knew what he was carry-
ing. More: the substance could have been analyzed by the
defense. The Treasury would have paid for a chemist to
analyze it on defendant’s behalf. 18 U.S.C. §3006A(e)(1).
Because the substance was available to both sides, there
cannot have been a Brady problem.
  If Banks thought that the substance was not cocaine (or
even that there was a serious question about its composi-
No. 07-3348                                                19

tion), defense counsel would not have relied exclusively
on trying to impeach the DEA’s chemist—and at trial
defense counsel did not even try to impeach Browning.
(Counsel waived cross-examination.) To challenge Brown-
ing’s conclusions, the defense would have needed its
own expert and could have had the substance analyzed
readily. Yet Banks has never denied that the substance
is cocaine and has never had it tested (at least, has not
argued that tests undermine Browning’s results; perhaps
a defense expert confirmed Browning’s conclusions). It
would be absurd to hold a new trial to establish, for
a second time, something that is uncontested.
  Once Browning’s credit-card problem came to light, and
the prosecutor said that it would have been easy to use
another chemist, the district judge had to decide what
would have happened. The evidentiary hearing at which
Browning testified about her finances should have ex-
plored two other issues: First, would the prosecution
have used another chemist? Second, what would this
other chemist have said? Suppose the prosecutor had
testified that he would have used another chemist, and
the judge had believed this. Then there would be no
basis for another trial, unless there is good reason to
think that the second chemist would reach a conclusion
different from Browning’s. And the best way to find out
is to appoint an independent (non-DEA) expert and
have that expert analyze the substance.
  This case went off the rails because the parties failed to
alert the district judge to the distinction between verifiable
and non-verifiable testimony. When impeaching evidence
20                                              No. 07-3348

about a non-verifiable subject (such as whether a witness
saw the defendant shoot the victim) comes out after trial,
the only way to probe that subject’s significance is to
hold another trial with all evidence placed before the jury.
But for a question such as “is substance X cocaine or
sugar?”, there is a way to explore materiality without a
new trial. Unless a fresh expert analysis of the substance
would undermine Browning’s analysis, a new trial would
be pointless. The defense bears the burdens of production
and persuasion on Brady claims; the gaps in the record
mean that the outcome of the trial stands.




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