                             In the
 United States Court of Appeals
               For the Seventh Circuit
                          ____________

No. 05-2791
UNITED STATES OF AMERICA,
                                                 Plaintiff-Appellee,
                                 v.

TONY L. WARREN,
                                            Defendant-Appellant.
                          ____________
            Appeal from the United States District Court
       for the Northern District of Illinois, Eastern Division.
            No. 03-CR-113-2—Elaine E. Bucklo, Judge.
                          ____________
      ARGUED APRIL 14, 2006—DECIDED JULY 27, 2006
                     ____________


 Before BAUER, ROVNER, and EVANS, Circuit Judges.
  ROVNER, Circuit Judge. Tony Warren was convicted of
various charges related to a fraudulent check scheme. What
makes Warren’s convictions unusual is his insistence that
the fraud was authorized by the United States Secret
Service. Warren stipulated that he sent several altered
checks purportedly made out to “A&B Electrical” to an
individual named Robert Studnicka, who cashed them and
kept a portion of the proceeds for himself. Police caught
Studnicka, who cooperated and implicated Warren in the
scheme. The two were charged in a nine-count superseding
indictment with violating 18 U.S.C. §§ 1344 (prohibiting
bank fraud), 2314 (forbidding transporting forged and
fraudulent checks in interstate commerce), and 513 (prohib-
2                                              No. 05-2791

iting making, uttering, or possessing forged securities).
Studnicka pleaded guilty, but Warren went to trial, claim-
ing that his behavior was authorized because he was a
confidential informant for the United States Secret Service.
The jury disbelieved Warren’s defense, and convicted him
on all counts. Warren now appeals, raising a number of
alleged errors at both trial and sentencing.


                             I.
   Although the details remain murky, the premise of the
check scheme is fairly straightforward. Legitimate checks
issued by corporations such as Whirlpool and National
Geographic, among others, were altered so that the
payee on each check was A&B Electric, a company owned by
Studnicka. Warren, who was living in New York at the
time, then sent the altered checks to Studnicka, who was
living in Illinois (Warren has never disclosed how he
obtained the checks). Studnicka then deposited the checks,
which ranged in amount from $65,000 to $280,000, into his
bank accounts at Palos Heights Bank and Trust and First
Midwest Bank. Generally Studnicka would withdraw
proceeds from the checks to send to Warren (between
$20,000 to $30,000) and keep the remainder for himself.
Warren and Studnicka repeated this pattern approximately
five times between December 2002 and January 2003. That
same month, Studnicka was arrested, owing in part to
suspicion raised by the failure of a $214,000 check he
deposited at Palos Heights Bank and Trust to clear.
  After Studnicka’s arrest, he agreed to cooperate in the
investigation against Warren. Under the direction of federal
agents, Studnicka persuaded Warren to come to Illinois to
pick up his remaining share of the checks that Studnicka
had cashed. Warren agreed to meet Studnicka at a mall in
Matteson, Illinois, ostensibly to recover approximately
$200,000 that he believed Studnicka still owed him.
No. 05-2791                                               3

Studnicka met Warren in the parking lot, and agents
arrested both men. The government indicted them in April
2003, and returned a superseding indictment in August
2003.
  Warren admitted giving the checks to Studnicka, but he
provided an unusual justification: he claimed he was
working as a confidential informant for the Secret Service
in New York. The government initially denied that Warren
had ever worked as a confidential informant. Then in
August 2003, the government acknowledged that Warren
had worked as a confidential informant for a brief
period between March and April 2001. The government
submitted two affidavits from Douglas Farrell, a Chicago-
based Secret Service agent who had investigated the
pending charges against Warren. The first affidavit ex-
plained that when they first explored Warren’s claim that
he was a confidential informant, the New York Secret
Service offices were unable to confirm the claim. After
contacting the Secret Service Investigative Support Divi-
sion, however, Chicago Secret Service agents learned that
Warren had in fact worked briefly as a confidential infor-
mant, but that he had been “formally deactivated” in April
2001. Farrell’s second affidavit, tendered in response to a
court order for the government to provide Warren with “all
information relating to defendant’s status as a confidential
informant,” explained that the paperwork associated with
Warren’s service as a confidential informant had been
destroyed by the September 11, 2001 terrorist attacks on
the World Trade Center. Nearly a year later, in July 2004,
the government tendered a draft Secret Service report
detailing Warren’s work as a confidential informant. Secret
Service agent Brian Koch gave the report to prosecutors
during an interview, and they tendered it promptly to
Warren.
  In addition to Agent Farrell’s affidavits and Agent Koch’s
report, at Warren’s request the government facilitated a
4                                                No. 05-2791

telephone interview between Warren’s counsel and Secret
Service agent Matthew Quinn, who had worked with
Warren. Quinn provided background information about how
Warren became involved with the Secret Service. Quinn
explained that in February 2001 he worked on the “West
African Task Force,” investigating crimes com-
mitted primarily by Nigerian nationals in the United States
and overseas. Warren had come to the attention of the
Secret Service in 1999 when agents obtained a counterfeit
check made out to Warren and drawn on the Central Bank
of Nigeria. Nothing came of this initial contact, but Warren
later approached the Secret Service in early 2001, at which
point he had lost approximately $400,000 in a scam known
as an “advance fee fraud.” In one iteration of this scheme,
someone from Nigeria contacts a United States citizen
(often a small business owner who can readily access
capital) with a lucrative but somewhat shady “business”
venture. The story would be, for instance, that due to a
government contract overrun, between $20 and $40 million
of “free” money was tied up in Nigeria. With a cash bribe for
some Nigerian government official, however, the money
could be released. The individual contacted would be asked
to advance, for example, $10,000 or $15,000 for the bribe,
and would be promised anywhere from 10 to 50 percent of
the multi-million dollar sum in exchange. This fantastic-
sounding “opportunity” was accompanied by official-looking
documentation. The scheme did not stop after the first
$10,000 to $15,000. Instead, the perpetrator encountered a
series of supposed snags in accessing the money, each of
which required the victim to continue sending funds in
hopes of getting the big payoff or at least recouping his orig-
inal “investment.”
  As a victim of this scheme, Warren was enlisted by the
Secret Service to help infiltrate the Nigerian fraud ring and
bring one of its leaders to the United States for arrest.
According to agents who worked with Warren, his time as a
No. 05-2791                                                5

confidential informant was short-lived due to his frustration
with the pace of the investigation and ultimately his refusal
in March 2001 to turn over a counterfeit $3 million check.
In connection with this incident and a later independent
federal investigation into fraudulent checks, Warren was
arrested in June 2002 by federal officials in New York.
However, the complaint against him was later dismissed.
  Before his trial on the current charges, Warren stipulated
that he had caused the checks to be sent to Studnicka. His
trial thus centered on his public authority defense.
Studnicka testified against Warren, and the government
played taped conversations between Studnicka and Warren
made after Studnicka’s arrest. In the tapes, Warren refers
repeatedly to the “Nigerians,” and his need to go to the
“motherland” to get his money back.
  Two Secret Service agents who had worked with Warren
also testified. The first, Matthew Quinn, explained that
he and two other agents, Kevin Worthington and Brian
Koch, met with Warren in late 2000 or early 2001. After
seeing the documents Warren had received from the
perpetrators, the agents enlisted Warren as a confidential
informant. Shortly thereafter, at the beginning of March
2001, Quinn was transferred from the West African Task
Force to the presidential detail. Despite the transfer, Quinn
continued to work informally with Worthington and Koch
when the need arose. Quinn testified that one of his last
conversations with Warren was to tell him that he was no
longer to do anything on behalf of the Secret Service.
  In connection with that testimony, Warren’s counsel
asked Quinn what “deactivation” meant, to which Quinn
responded, “ ‘deactivation’ is not really a word that I would
use.” Believing that Quinn had used the term in his pre-
trial telephone interview, counsel sought to impeach Quinn
using the telephone interview, but the court sustained
the government’s objection.
6                                               No. 05-2791

  Agent Brian Koch, who had taken over supervising
Warren when Quinn was transferred, also testified. He
recounted that in April 2001 Warren had received a check
for $3 million from a Nigerian man named Dr. Oduebo.
Warren faxed Koch a copy of the check, and Koch in-
formed him that it was counterfeit. He testified that he told
Warren to hold on to the check until agents could come
retrieve it. But when Koch arrived to pick up the check,
Warren told Koch that he was too late; the check was gone.
Warren then left under the pretense of retrieving the check.
After waiting an hour or so for Warren to return, Koch left
and returned to his office. He later spoke to Warren on the
phone and informed him that he was no longer working as
an informant, and that if he tried to cash the check he
would be prosecuted.
  Warren testified in his own defense. He insisted that
Secret Service agents had never told him that he was no
longer to act as a confidential informant. Instead, he
maintained that he was authorized to do “whatever it takes”
to infiltrate the “Nigerian mob.” He claimed that he was
still acting pursuant to that mandate in late 2002 and early
2003 when he gave the fraudulent checks to Studnicka to
cash, and that as he sat testifying he remained in “deep
cover” pursuant to that mission. Warren also testified about
the earlier charges against him in New York. He used the
fact that those charges had been dropped to advance his
theory that he was still working as a confidential informant
at the time of his interaction with Studnicka nearly two
years after he began working as a confidential informant.
  After Warren rested his case, the government called
Assistant United States Attorney Richard Donoghue, who
had overseen the 2002 charges against Warren in New
York. According to Donoghue, Warren was never in-
dicted for several reasons. The decision to dismiss the
original criminal complaint was fueled by time constraints
and the fact that additional fraudulent checks were uncov-
No. 05-2791                                                   7

ered during the investigation of the initial charges.
Donoghue also testified that at least one check had been
destroyed in the World Trade Center on September 11.
Finally, Donoghue explained that when his office learned
about the indictment in Chicago, it decided to wait until
that prosecution concluded instead of conducting two
parallel prosecutions.
  Donoghue also testified that Warren had called him after
the New York charges were filed, “rambling” about it be-
ing “the season for checks” and claiming that he wanted
to “get the Nigerians.” When Donoghue reminded Warren
that his last attempt at cooperation had not been entirely
successful, Warren claimed that the Secret Service had
“bullshitted” him. Donoghue also rebuffed Warren’s attempt
to set up a private meeting with him. Donoghue had
contemporaneous notes from that conversation, which he
provided to prosecutors the night before testifying. Prosecu-
tors, in turn, provided the notes to Warren the morning of
Donoghue’s testimony. After Donoghue’s testimony, War-
ren’s counsel asked the court if Warren could take the stand
again to refute portions of Donoghue’s testimony. The
district court reluctantly agreed, but then Warren decided
against testifying further and both sides rested.
  The jury apparently disbelieved Warren’s public authority
defense, and convicted him on all counts (except Count 5,
which was dismissed). Warren moved for a new trial,
alleging that a number of trial errors deprived him of a fair
trial and that the government had withheld exculpatory
evidence relating to his status as a confidential informant.
The court denied his motion. At sentencing, the district
court declined to award Warren credit under the advisory
guideline range for acceptance of responsibility, see U.S.S.G.
§ 3E1.1, and also adjusted the advisory range upward based
on her finding that Warren obstructed justice by lying when
he testified at trial that he was still acting as a confidential
informant, see U.S.S.G. § 3C1.1. These calculations, com-
8                                               No. 05-2791

bined with Warren’s lack of any criminal history, resulted
in an advisory guideline range of 41 to 51 months. The court
sentenced Warren to 41 months imprisonment followed
by five years of supervised release, and ordered him to
pay full restitution of $177,905.49 (jointly and severally
with Studnicka).


                             II.
  Warren claims that his right to a fair trial was prejudiced
because the government withheld information relating to
his status as a confidential informant and belatedly dis-
closed Donoghue’s notes. He also argues that he was
prejudiced by his inability to impeach Agent Quinn with the
notes from his telephone interview. Finally, he attacks his
sentence and the jury instructions at his trial. We consider
his arguments in turn.


A. Motion for a New Trial
    1. Brady Violations
  First, Warren argues that the district court erred by
denying his motion for a new trial, premised on alleged
discovery and trial errors. He contends that the government
breached its discovery obligations by withholding informa-
tion about his status as a confidential informant. He points
in particular to the government’s failure to produce inde-
pendent written evidence of his “deactivation” as a confiden-
tial informant—evidence he insists exists based on Agent
Farrell’s affidavit to the effect that Warren was “formally
deactivated” in April 2001.
  In Brady v. Maryland, 373 U.S. 83 (1963), the Supreme
Court held that “the suppression by the prosecution of
evidence favorable to an accused . . . violates due process
where the evidence is material either to guilt or to pun-
No. 05-2791                                                  9

ishment, irrespective of the good faith or bad faith of the
prosecution,” id. at 87. In order to demonstrate a Brady
violation, Warren must make three showings: (1) that the
evidence is favorable to him because it is exculpatory or
impeaching; (2) that the prosecution suppressed the
evidence, either wilfully or inadvertently; and (3) that
“prejudice . . . ensued.” Strickler v. Greene, 527 U.S. 263,
281-82 (1999); see also United States v. Price, 418 F.3d 771,
785 (7th Cir. 2005). To demonstrate prejudice, Warren must
establish a reasonable probability that the result of the trial
would have been different if the evidence had been dis-
closed. Strickler, 527 U.S. at 280; see also United States v.
Childs, 447 F.3d 541, 545 (7th Cir. 2006). We review the
district court’s denial of a motion for a new trial premised
on alleged Brady violations for abuse of discretion, see
United States v. Elem, 269 F.3d 877, 881 (7th Cir. 2001),
viewing the evidence in the light most favorable to the
prevailing party, Childs, 447 F.3d at 544.
  The central thesis of Warren’s Brady claim is that the
government has not been forthcoming with documentation
of his service as a confidential informant and has never
produced a written document informing Warren that he is
no longer a confidential informant. In denying Warren’s
motion for a new trial, the district court pointed out that
Warren had failed to establish that such a document exists.
Warren now faults the district court for focusing too much
on a “deactivation” form and overlooking Warren’s argu-
ment that the government withheld other information as
well. Warren, however, fails to identify any such “other
information” with precision. Instead, he takes aim at the
government’s responses to discovery in general, pointing
to its initial denial of his claim that he was a confidential
informant, its failure to mention the September 11 terrorist
attacks as a reason it lacked information until Farrell’s
second affidavit, and the late production of Brian Koch’s
draft Secret Service report. Warren argues that the govern-
10                                               No. 05-2791

ment’s shifting position on the evidence it did disclose
necessarily means other evidence must have been withheld.
He also continues to insist that Agent Farrell’s use of the
phrase “formally deactivated” means there must be some
official document stating that Warren no longer works as a
confidential informant.
  Whether limited to an alleged document deactivating
Warren as a confidential informant or expanded to in-
clude the universe of all documentation of Warren’s confi-
dential informant activities, the result is the same. As the
district court recognized, Warren is simply unable to point
to any specific evidence, exculpatory or otherwise, withheld
by the government. Without that, his Brady claim fails to
get off the ground. See Price, 418 F.3d at 785 (no Brady
violation where no document existed corroborating defen-
dant’s claim of alleged agreement between government and
prosecution witness). Even assuming the existence of such
evidence, it is far from clear that it would be exculpatory or
impeaching. Take for instance Warren’s insistence that
there must be some document “deactivating” him as a
confidential informant. Far from exonerating Warren, such
a document would undercut his public authority defense
and deprive him of one of his theories of defense: that he
never received any official notice informing him that he was
no longer a confidential informant, and he thus continued
to believe at the time he committed the offenses that he was
infiltrating the Nigerian fraud ring on behalf of the Secret
Service.
  Without any evidence that the government withheld
information, Warren’s claim is reduced to a complaint about
the timing of various government revelations. Warren,
however, fails to explain what he would have done differ-
ently if the government had admitted earlier that he was a
confidential informant or provided information, such as
Agent Koch’s report, sooner. Late disclosure does not itself
No. 05-2791                                                 11

constitute a Brady violation. See United States v. O’Hara,
301 F.3d 563, 569 (7th Cir. 2002). Warren used all of the
information the government did provide and built a defense
around his claim that he was a confidential informant. Id.
at 569 (no Brady violation where government disclosed
information during trial but defendant had sufficient time
to make use of it); see also United States v. Knight, 342 F.3d
697, 708-09 (7th Cir. 2003) (no Brady violation where
defendant made effective use of evidence despite govern-
ment’s late disclosure). The district court thus did not abuse
its discretion by denying his motion for a new trial premised
on documentation related to his status as a confidential
informant.


  2. Donoghue’s Notes
  Likewise, the district court was within its discretion to
conclude that Warren was not entitled to a new trial based
on the government’s handling of Assistant United States
Attorney Richard Donoghue’s notes from his 2002 conversa-
tion with Warren. As discussed above, the government
called Donoghue to refute the inference created by Warren’s
testimony that the New York charges against him were
dismissed because he was a confidential informant. Shortly
before Donoghue took the stand, the government produced
the notes he had made memorializing Warren’s odd Novem-
ber 2002 call requesting a private meeting. Warren argues
that by failing to produce the notes earlier, the government
violated Brady and Federal Rule of Criminal Procedure 16.
  Rule 16 requires the government, at the defendant’s
request, to disclose “the substance of any relevant oral
statement made by the defendant, before or after arrest,
in response to interrogation by a person the defendant knew
was a government agent if the government intends to use
the statement at trial.” Fed. R. Civ. P. 16(a)(1)(A). The trial
court has discretion to fashion a remedy for the govern-
ment’s noncompliance with Rule 16, United States v. De La
12                                               No. 05-2791

Rosa, 196 F.3d 712, 715 (7th Cir. 1999), and this court will
not disturb the district court’s decision absent a showing of
abuse of discretion and prejudice, United States v. Breland,
356 F.3d 787, 797 (7th Cir. 2004). Although Warren re-
quested a new trial, such a remedy is warranted only when
“all other, less drastic remedies are inadequate.” De La
Rosa, 196 F.3d at 715. Additionally, a new trial is appropri-
ate only if the alleged Rule 16 violation deprived Warren of
a fair trial. See United States v. Miller, 199 F.3d 416, 420
(7th Cir. 1999).
  Warren’s inability to establish prejudice dooms his claim.
Assuming Donoghue’s notes were in fact protected by Rule
16 (made as they were in response to Warren’s call to
Donoghue, the applicability of the Rule is far from clear),
Warren was prejudiced by their belated production only
if he was “unduly surprised” and lacked “an adequate
opportunity to prepare a defense.” Breland, 356 F.3d at 797.
The government produced the notes before Donoghue
testified, and Warren does not argue on appeal that he
would have mounted a different defense had he obtained
the notes sooner. Instead, he asserts generally that
Donoghue’s handwritten notes “related to the central issue
of defendant’s status as a CI and his defense of public
authority.” But this point is irrelevant unless the timing
of the notes’ production somehow prevented Warren from
using them in his defense. Indeed, he did not request a
continuance when the notes were disclosed, Fed. R. Crim.
P. 16(d)(2)(B) (authorizing court to grant continuance for
non-compliance with Rule 16), and at a sidebar after
Donoghue’s testimony counsel decided against having
Warren take the stand again. Because Warren’s counsel
made use of the notes in his cross-examination, and Warren
does not explain what he would have done differently had
he obtained them earlier, the district court did not abuse its
discretion by denying his motion for a new trial premised on
the notes. Breland, 356 F.3d at 797; De La Rosa, 196 F.3d
No. 05-2791                                               13

at 716-17 (no prejudice where defendant rejected court’s
offer of continuance and no bad faith was shown on govern-
ment’s part); see also Knight, 342 F.3d at 705-06 (no Brady
violation when government disclosed impeachment evidence
in time for defendants to incorporate information into cross-
examination).


  3. Impeachment of Agent Quinn
  Warren next argues that the he was denied a fair trial
because the district court refused to allow him to cross-
examine Agent Quinn with what Warren characterizes as
Quinn’s prior inconsistent statement. While cross-examin-
ing Quinn, Warren’s counsel asked him what the term
“deactivation” meant, to which Quinn responded, “‘deactiva-
tion’ is not really a word that I would use, but it’s—I’m
assuming you are asking if it is applying towards taking
a CI who is activated and deactivating him.” Counsel
then attempted to seize on Quinn’s representation that
“deactivation” was not really a term he would use and
suggest that he had in fact used the term in his pre-trial
telephone interview. During that interview, the government
asked Agent Quinn if he recalled “when Tony [Warren] was
deactivated as a CI” and “why it was he was deactivated.”
Defense counsel then asked Quinn what he meant by
“deactivation,” to which Quinn responded, “[d]eactivation
just simply means the—no longer using an individual as an
informant.” In response to continuing questions from
counsel, Quinn used the term “deactivation” several other
times during the interview.
  This exchange forms the basis for Warren’s claim that he
was denied an opportunity to impeach Quinn with his prior
inconsistent statement. Believing the telephone interview
could not be used because it was unsworn, the district court
denied Warren’s attempt to refer to it at trial. When
Warren later moved for a new trial, he represented to the
14                                              No. 05-2791

court that he had been denied the opportunity to impeach
Quinn’s testimony on the issue of whether Quinn “told
Warren he was deactivated.” At that point, the district court
acknowledged that it may have erroneously excluded the
prior statement on the grounds that it was unsworn, and so
ordered further briefing on whether its refusal to allow the
“impeachment” was harmless. After reviewing Quinn’s
testimony against the actual transcript of the telephone
interview, however, the district court concluded that there
was no inconsistency, and thus no error in its decision to
prohibit the “impeachment.” We review the district court’s
decision for abuse of discretion. See United States v. Heath,
447 F.3d 535, 538 (7th Cir. 2006).
  We agree with the district court that any error in disal-
lowing the statement was harmless because Quinn’s trial
testimony is not inconsistent with his telephone interview.
In the telephone interview, Quinn was repeatedly asked if
he told Warren that he was “deactivated.” Agent Quinn
responded, that no, he did not tell Warren that he was
“deactivated,” but he did tell Warren that he was no longer
authorized to do anything on behalf of the Secret Service.
Then at trial Agent Quinn testified that “deactivation” is
not a term that he uses. The fact that Agent Quinn repeated
the word “deactivation” during the telephone interview does
not undercut his trial testimony that he does not use the
word “deactivation” to tell someone that he is no longer a
confidential informant.
  In his brief Warren makes much of what he characterizes
as the district court’s admission of error regarding the
statement’s admissibility. But his argument ignores the
district court’s ultimate finding that any error was
harmless—a finding that is not clearly erroneous in light of
the fact that Quinn’s statements in the telephone interview
were not actually inconsistent with his trial testimony. See
United States v. Douglas, 408 F.3d 922, 927 (7th Cir. 2005)
No. 05-2791                                                15

(rejecting defendant’s argument that district court errone-
ously limited cross-examination because the “so-called
impeachment evidence was not relevant”); United States v.
Akinrinade, 61 F.3d 1279, 1287 (7th Cir. 1995) (upholding
district court’s refusal to issue jury instruction regarding
prior inconsistent statements when “[t]here simply were no
clear inconsistencies in testimony”).


B. Sentencing
  Warren next takes issue with two of the district court’s
decisions at sentencing. First, he contends that the district
court erroneously imposed an upward adjustment to his
sentence for obstruction of justice. Relatedly, he takes issue
with the district court’s failure to give him credit
for acceptance of responsibility.
  Under § 3C1.1 the district court may enhance a defen-
dant’s sentence two levels after finding that he willfully
obstructed or impeded justice during the offense of con-
viction. See U.S.S.G. § 3C1.1. The comments to that guide-
line list “committing, suborning, or attempting to suborn
perjury” as behavior warranting the enhancement. How-
ever, as Warren points out, neither denying guilt nor
testifying and later being found guilty themselves provide
a basis for the enhancement. U.S.S.G. § 3C1.1, comment,
n.2. Thus, if a defendant objects “to a sentence enhance-
ment resulting from her trial testimony, a district court
must review the evidence and make independent findings
necessary to establish a willful impediment to or obstruc-
tion of justice.” United States v. Dunnigan, 507 U.S. 87, 95
(1993); see also United States v. Williams, 272 F.3d 845, 864
(7th Cir. 2001). We review the district court’s application of
the Guidelines de novo and its factual determinations for
clear error. See United States v. Davis, 442 F.3d 1003, 1008-
09 (7th Cir. 2006).
 Warren did challenge the obstruction-of-justice adjust-
ment, and the district court made appropriate factual
16                                              No. 05-2791

findings to support it. On appeal, Warren renews his
argument that the jury’s guilty finding alone does not lead
to the conclusion that he lied under oath. He could, for
example, honestly have believed that he was acting as a
confidential informant, and the jury could still have found
him guilty on the grounds that his belief was unreasonable.
The district court recognized this and made its own findings
as follows: “[W]hat we have here is that I need to make a
finding, and unfortunately I do find that he made material
misstatements under oath on the stand.” The court went on
to point out that it was authorized to decide that Warren
had obstructed justice, and found specifically that, “when he
said that these agents all said that his conduct would be
legal, that he knew that that was not true . . . when he
asserted that Agent Brian Koch was not truthful when he
claimed he deactivated the defendant, that the defendant
knew that was not true . . . when he said that no one ever
told him to stop working for the Secret Service, that he
knew that that was not true . . . when he said that the
Secret Service authorized his activity with respect to the
checks charged in the indictment, he knew that was not
true; and when he said that he was still in deep cover, he
knew that that was not true.”
  Unsatisfied with these findings, Warren argues that
in the wake of United States v. Booker, 543 U.S. 220 (2005),
the jury must make the factual findings necessary to
support an obstruction-of-justice enhancement. His argu-
ment is meritless. As we recently recognized in another
obstruction-of-justice case, the Supreme Court in
Booker “held that a Sixth Amendment problem arises where
the sentence exceeds the statutory maximum for
the charged crime or is imposed under a mandatory sen-
tencing scheme, not that district courts may not conduct
judicial fact-finding.” United States v. White, 443 F.3d 582,
592 (7th Cir. 2006). White continues, “[t]o the contrary,
‘Booker resolved the problem by making the guidelines
No. 05-2791                                               17

advisory; judicial fact-finding in sentencing is acceptable
because the guidelines are now nonbinding.’ ” Id. (quoting
United States v. Robinson, 435 F.3d 699, 701-02 (7th Cir.
2006)). Thus, the district court was authorized to find that
Warren testified falsely as to a material issue, namely,
whether he believed he was acting as a confidential infor-
mant at the time he committed the fraud with Studnicka.
Warren does not suggest, nor could he, that the factual
findings themselves are clearly erroneous. We see no error
in the district court’s discharge of its duty to make inde-
pendent findings under the definition of perjury, Dunnigan,
507 U.S. at 87, as required to support the enhancement.
  It follows from this conclusion that the court did not err
by denying Warren credit for acceptance of responsibility
under § 3E1.1 of the Sentencing Guidelines. The com-
ments to § 3E1.1 state that conduct resulting in an en-
hancement for obstruction of justice “ordinarily indicates
that the defendant has not accepted responsibility for his
criminal conduct.” U.S.S.G. § 3E1.1, comment, n.4. Add to
that the fact that the adjustment is “not intended to apply
to a defendant who puts the government to its burden of
proof at trial by denying the essential factual elements of
guilt,” id. comment, n.2, and Warren faces an uphill battle.
Warren maintains without elaboration that he accepted
responsibility by stipulating that he sent the fraudulent
checks to Studnicka. He also claims he should not be denied
credit under § 3E1.1 because of his “genuine belief” that he
was acting as a confidential informant. The district court’s
findings as to Warren’s obstruction of justice, however,
undercut such a theory. Moreover, Warren fails to explain
what is extraordinary about his case, and he did put the
government to its burden of proof by maintaining that none
of his conduct was unlawful because he was acting as a
confidential informant. It was thus not clearly erroneous for
the district court to deny Warren points for acceptance of
responsibility. See Davis, 442 F.3d at 1010.
18                                               No. 05-2791

C. Jury Instructions
  That leaves Warren’s cursory challenges to several jury
instructions and the special verdict forms given in his case.
Citing Blakely v. Washington, 542 U.S. 296 (2004), without
any explanation of its applicability, he claims that three
of the jury instructions should have required the govern-
ment to prove beyond a reasonable doubt that his public
authority defense was invalid. And without any citation
at all, he claims it was improper for the court to admonish
the jury not to consider Warren’s possible sentence when
reaching its verdict. Warren provides no argument to
support his unelaborated claim that the pattern jury
instructions he disputes were invalid, nor can we see any
reason for finding as much. Likewise, he provides no
authority to support his claim that the court’s use of special
verdict forms to determine actual and intended
loss deprived him of a fair trial. Accordingly, he has waived
any challenge to the jury instructions or the special verdict
forms. See United States v. Turcotte, 405 F.3d 515, 536 (7th
Cir. 2005) (“In this circuit, unsupported and undeveloped
arguments are waived.”).


                            III.
  For the foregoing reasons, we AFFIRM Warren’s convic-
tions and sentence.
No. 05-2791                                         19

A true Copy:
      Teste:

                    ________________________________
                    Clerk of the United States Court of
                      Appeals for the Seventh Circuit




               USCA-02-C-0072—7-27-06
