                               In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 14-1390
UNITED STATES OF AMERICA,
                                                   Plaintiff-Appellee,

                                 v.

RONALD KIELAR,
                                               Defendant-Appellant.
                     ____________________

         Appeal from the United States District Court for the
           Northern District of Illinois, Eastern Division.
          No. 1:10-cr-00691-1 — Robert M. Dow, Jr., Judge.
                     ____________________

     ARGUED DECEMBER 4, 2014 — DECIDED JUNE 29, 2015
                     ____________________

   Before BAUER, RIPPLE, and SYKES, Circuit Judges.
    RIPPLE, Circuit Judge. Ronald Kielar was convicted in the
United States District Court for the Northern District of Illi-
nois on charges arising out of a scheme to defraud two
health insurance companies by submitting fraudulent claims
for the prescription drug Procrit. He now appeals his convic-
tion, alleging several procedural and evidentiary errors. For
the reasons set forth in this opinion, we affirm the judgment
of the district court.
2                                                       No. 14-1390

                                  I
                        BACKGROUND
    Ronald Kielar was a licensed pharmacist at the Cartagena
Pharmacy in Chicago, Illinois. Many of Mr. Kielar’s patients
came from the medical practice of Dr. Camilo Barros, whose
office was located in the same building as the Cartegena
Pharmacy. Starting in November 2004, Mr. Kielar began de-
frauding two health insurance companies, Blue Cross and
Blue Shield of Illinois (“BCBS”) and United Food and Com-
mercial Workers Union and Employers Midwest Health
Benefit Fund (“UFCW”), by submitting fraudulent claims for
the prescription drug Procrit. 1 In particular, Mr. Kielar
forged prescriptions for Procrit under Dr. Barros’s name and
then submitted those prescriptions to BCBS and UFCW for
payment. He knew at the time that Procrit had neither been
prescribed, nor provided, to any of the individuals under
whose policies he sought reimbursement. His scheme con-
tinued over roughly six years and resulted in losses to BCBS
and UFCW of approximately $1,678,549.
    In August 2010, Mr. Kielar was indicted on five counts of
health care fraud in violation of 18 U.S.C. § 1347. This in-
dictment also contained a forfeiture allegation, pursuant to
18 U.S.C. § 982(a)(7), for any proceeds of Mr. Kielar’s fraudu-
lent scheme. This allegation specifically identified three of
Mr. Kielar’s properties as subject to forfeiture, including a
property located at 12786 NW 75th Street, Parkland, Florida
(the “Florida Property”).



1 Procrit is an intravenous drug used to treat patients suffering from
chronic kidney failure, cancer, or HIV infection.
No. 14-1390                                                   3

    Later that month, the Government filed a notice of lis
pendens for the Florida Property based on the indictment’s
forfeiture allegation. Shortly thereafter, Mr. Kielar filed a
motion requesting permission to sell the Florida Property,
stating that he needed the proceeds of the sale in order to
pay his attorneys’ legal fees. In its response, the Government
stated that it did not object to the sale, provided that
Mr. Kielar deposit the sale proceeds in an escrow account
with the United States Marshals Service.
    In October 2010, the district court granted Mr. Kielar’s
motion to release the lis pendens and allow for the sale of his
Florida Property. Consistent with the Government’s request,
however, the court ordered that the proceeds of the sale be
placed in an escrow account with the United States Marshals
Service. Shortly after doing so, Mr. Kielar filed another mo-
tion asking the district court to vacate its earlier order and
allow him to use the sale proceeds “for taxes, legal fees and
other expenses.” 2 After several rounds of briefing, the dis-
trict court denied Mr. Kielar’s request and, shortly thereafter,
also denied his motion for reconsideration.
    In March 2013, a grand jury returned a ten-count super-
seding indictment against Mr. Kielar, charging him with six
counts of health care fraud, in violation of 18 U.S.C. § 1347;
three counts of aggravated identify theft, in violation of 18
U.S.C. § 1028A(a)(1); and one count of using false records to
impede a federal investigation, in violation of 18 U.S.C.
§ 1519. Like the initial indictment, the superseding indict-
ment also contained a forfeiture allegation pursuant to 18
U.S.C. § 982(a)(7).

2   R.36 at 2.
4                                                              No. 14-1390

   Following a week-long jury trial, Mr. Kielar was convict-
ed on all charges. 3 He timely appealed. 4


                                      II
                              DISCUSSION
   Mr. Kielar contends that the district court erred on three
separate grounds: (1) by failing to hold an evidentiary hear-
ing on his request to release his escrowed funds, (2) by limit-
ing his cross-examination of Dr. Barros, a key government
witness, and (3) by preventing him from calling Fernando
Perez as a defense witness. We address these issues in turn.


                                      A.
    We begin with Mr. Kielar’s contention that the district
court erred by failing to hold an evidentiary hearing on his
request to release his escrowed funds. Because this conten-
tion concerns the scope of Mr. Kielar’s rights under the Due
Process Clause, our review is de novo. United States v.
Kirschenbaum, 156 F.3d 784, 792 (7th Cir. 1998).


                                      1.
    Mr. Kielar first requested that the district court release
his escrowed funds in November 2010, shortly after the sale
of his Florida Property. In particular, Mr. Kielar filed a mo-
tion asserting that the restraint on his access to those funds

3   The district court’s jurisdiction was premised on 18 U.S.C. § 3231.
4   Our jurisdiction over this appeal is secure under 28 U.S.C. § 1291.
No. 14-1390                                                    5

impeded his ability to pay his attorneys’ legal fees in viola-
tion of his Sixth Amendment right to counsel. Notably, this
motion contained neither documentary evidence nor specific
factual allegations demonstrating Mr. Kielar’s need for the
sale proceeds to finance his defense.
    The Government opposed the motion. It submitted that
the restraint on Mr. Kielar’s assets did not violate his Sixth
Amendment right to counsel because he had not shown,
“beyond the conclusory statements in his reply,” a “bona
fide need” for the assets. 5 The Government’s brief also ex-
plained how it could trace the proceeds of Mr. Kielar’s
fraudulent scheme from the corporate bank account of the
Cartegena Pharmacy to mortgage payments on the Florida
Property.
   In December 2010, the district court held a status hearing
at which defense counsel stated that Mr. Kielar’s motion
“may require a more detailed hearing.” 6 Counsel then re-
quested that the district court allow for additional briefing
on the issue. The district court granted the request.
   In January 2011, Mr. Kielar submitted a brief in support
of his November 2010 motion. Although the brief contained
several legal arguments, the only allegations in the brief con-
cerning Mr. Kielar’s need for the funds to pay his legal fees
were as follows:
               Over the past four and a half months, De-
           fendant Kielar has fallen behind in payments
           to his attorneys and is now in arrears for a sub-

5   R.40 at 4.
6   R.168 at 4.
6                                                   No. 14-1390

          stantial sum. Defendant Kielar’s inability to
          pay is due to the forfeiture clause which the
          Government included in the Indictment.…
          ….
          …Defendant Kielar has demonstrated a bona
          fide need for those funds because his attorneys
          can no longer afford to represent him on an es-
          sentially pro bono basis. Defendant Kielar’s
          counsel has invested immense time and sub-
          stantial money in his defense. To prevent the
          release of funds in escrow to Defendant
          Kielar’s attorneys would be to force them to
          withdraw from this case. As such, the court is
          essentially depriving Defendant Kielar of his
          Sixth Amendment right to the counsel of his
          choice and such a deprivation cannot stand.
          This Court must allow the release of sale pro-
          ceeds from the Florida Property in order to al-
          low the defendant to continue to retain his
          chosen counsel.[ 7]
Mr. Kieler did not submit any documentary evidence to sub-
stantiate these claims.
   In response, the Government again submitted that
Mr. Kielar’s motion should be denied because he had failed
to demonstrate a bona fide need for the assets at issue. The
Government further asserted that, assuming that Mr. Kielar
had shown a bona fide need, it had already demonstrated
adequately the basis for its forfeiture allegation.


7   R.42 at 2, 4 (emphasis in original).
No. 14-1390                                                          7

    In reply, Mr. Kielar submitted a one-and-a-half-page af-
fidavit in which he swore to the following facts: (1) that the
combined pharmacy salaries for him and his ex-wife (with
whom he lived) were only enough to pay minimal living ex-
penses, (2) that he derived the down payment for the Florida
Property from refinancing his house in Illinois, which was
purchased in 1999, (3) that he owned a 2002 automobile with
200,000 miles, (4) that he owned two Met Life insurance pol-
icies with limited equity, and (5) that he was unable to pay
his attorneys’ fees without the release of funds. Mr. Kielar
did not submit any further documentary evidence to sub-
stantiate these assertions.
   In February 2011, the district court denied Mr. Kielar’s
request to release the proceeds from the sale of his Florida
Property. In doing so, the district court relied on our deci-
sion in United States v. Moya-Gomez, 860 F.2d 706 (7th Cir.
1988), as setting forth the relevant legal standard for as-
sessing Mr. Kielar’s claim:
       [A] defendant whose assets may be subject to
       forfeiture may make out a Sixth Amendment
       right-to-counsel claim only if (1) he can estab-
       lish “a bona fide need to utilize assets subject to
       the restraining order to conduct his defense”
       and (2) the Government fails to “demonstrate
       the basis for its assertion, contained in the in-
       dictment, that the assets are subject to forfei-
       ture.”[ 8]



8R.46 at 2 (quoting United States v. Moya-Gomez, 860 F.2d 706, 730 (7th
Cir. 1988).
8                                                 No. 14-1390

    With regard to the first prong of this test, the district
court noted that the only evidence of a bona fide need sub-
mitted by Mr. Kielar was his one-and-a-half-page affidavit.
Although the court acknowledged that this “affidavit
lack[ed] detail and [was] not supported by any additional
materials (e.g., bank statements, pay stubs, etc.) that might
make a more convincing showing of need,” it nonetheless
“assume[d], without deciding, that Defendant [had] shown a
bona fide need for the restrained assets to support his de-
fense.” 9 From there, the court went on to conclude that the
Government had offered sufficient evidence to show that the
seized assets at issue were subject to forfeiture and, accord-
ingly, that Mr. Kielar was not entitled to the release of his
escrowed funds. In a footnote to this discussion, the court
noted that Mr. Kielar had “not requested a formal eviden-
tiary hearing on this issue,” yet concluded that such a hear-
ing was unnecessary given that Mr. Kielar had been afforded
“ample opportunity to present argument (in four briefs) and
evidence (in the form of his affidavit).” 10
    At a subsequent status hearing, Mr. Kieler requested that
the district court reconsider its February 2011 order. The dis-
trict court agreed to do so and suggested additional briefing.
Shortly afterward, Mr. Kielar filed a written motion for re-
consideration. However, he still did not submit any further
evidence to substantiate his need for the escrowed funds to
finance his defense, nor did he request an evidentiary hear-
ing on the issue. Notably, however, his motion did state that
he, as the defendant, did “not bear the burden to request a


9   Id. at 3.
10   Id. at 4 n.1.
No. 14-1390                                                   9

formal evidentiary hearing on this issue as the court [previ-
ously had] indicate[d].” 11
    In May 2011, the district court again denied Mr. Kielar’s
request to release his escrowed funds. Once again, the court
assumed without deciding that Mr. Kielar had established a
bona fide need for the assets at issue. Turning to the second
step of the Moya-Gomez analysis, the court determined that
the Government adequately had demonstrated the factual
basis for its forfeiture assertion and that “[a]t no time in any
of the written submissions or hearings before the
Court…ha[d the] Defendant come forward either with ar-
gument or evidence to rebut the Government’s conten-
tions.” 12 Further, the court again noted that Mr. Kielar had
not “at any time, including at the most recent status hear-
ing…, requested an evidentiary hearing to challenge the
Government’s analysis or develop the factual basis for a
counterargument.” 13
    At a subsequent status hearing, defense counsel asserted
that the district court’s order “le[ft] open a couple of ques-
tions” including “whether [Mr. Kielar] would be seeking an
evidentiary hearing.” 14 In response, the district court noted
that Mr. Kielar had neither previously requested a hearing
nor offered any argument or evidence to dispute the Gov-
ernment’s showing of traceability. This being the case, the
court asked what would happen at a hearing beyond the


11   R.52 at 3.
12   R.55 at 2.
13   Id.
14   R.165 at 3.
10                                               No. 14-1390

Government’s simply presenting the same evidence that it
already had provided in its briefs. Defense counsel initially
responded that if an evidentiary hearing were held,
Mr. Kielar would not present any evidence because it was
not his burden to do so. Defense counsel then acknowledged
that he and Mr. Kielar had not yet decided how to pursue
this issue and therefore asked for “some time to go over this
with Mr. Kielar.” 15 The district court granted this request
and gave defense counsel thirty days to confer with his cli-
ent.
    At the next status hearing on July 8, 2011, defense coun-
sel stated that he had conferred with Mr. Kielar and that
they would “not be asking for an evidentiary hearing con-
cerning the funds.” 16


                             2.
    Mr. Kielar now contends that the district court erred by
failing to order, sua sponte, an evidentiary hearing on his
request to release his escrowed funds. Specifically, he con-
tends that the court’s failure to do so “violated his Fifth
Amendment due process rights by depriving [him of] his
liberty interest under the Sixth Amendment to obtain coun-
sel of his choice.” 17
   With regard to certain federal criminal offenses, includ-
ing the health care fraud offense at issue here, a district


15   Id. at 11.
16   R.166 at 2.
17   Appellant’s Br. 12.
No. 14-1390                                                    11

court, upon the filing of an indictment containing a forfei-
ture allegation, may enter a protective order to preserve the
availability of a defendant’s assets that are subject to forfei-
ture. See 18 U.S.C. § 982(a)(7), (b)(1); 21 U.S.C. § 853(e)(1)(A).
In Moya-Gomez, 860 F.2d at 730, we held that a defendant in
such circumstances has a limited due process right to contest
the Government’s forfeiture allegation if the pretrial seizure
of his assets would prevent him from hiring the counsel of
his choice. In particular, Moya-Gomez held that if “the de-
fendant presents a bona fide need to utilize assets subject to
the restraining order to conduct his defense” and “the dis-
trict court finds that the defendant does not have other as-
sets from which such payments can be made,” the court
“then must require the government to demonstrate the basis
for its assertion, contained in the indictment, that the assets
are subject to forfeiture.” Id. With regard to the specific pro-
cess that was due, we held that such a defendant was enti-
tled to “an immediate, postrestraint, adversary hearing” up-
on making the requisite showing of bona fide need. Id. at
731. In subsequent cases, we have clarified that in order to
demonstrate a “bona fide need” a defendant must do more
than “submit[] a bare-bones affidavit asserting that he per-
sonally lack[s] sufficient funds to obtain counsel of his
choice.” Kirschenbaum, 156 F.3d at 792.
    The Government submits that Mr. Kielar waived his
right to a hearing under Moya-Gomez when, on July 8, 2011,
his counsel informed the district court that Mr. Kielar would
“not be asking for an evidentiary hearing concerning the
funds.” 18 Further, the Government contends that, waiver


18   R.166 at 2.
12                                                No. 14-1390

aside, Mr. Kielar was not entitled to an evidentiary hearing
because he never presented sufficient evidence to establish a
bona fide need for the assets at issue.
    The Government’s assertion of waiver is correct. Indeed,
the waiver here hardly could have been clearer. After having
thirty days to confer with his counsel over whether to re-
quest an evidentiary hearing, Mr. Kielar expressly declined to
request one. The record contains, moreover, no indication
that this decision was not a knowing and voluntary one. Nor
does Mr. Kielar contend otherwise. This decision thus falls
squarely within the definition of waiver: it was “the inten-
tional relinquishment of a known right.” United States v. Ro-
driguez-Gomez, 608 F.3d 969, 972 (7th Cir. 2010).
    Mr. Kielar now attempts to avoid this conclusion by as-
serting that the hearing right described in Moya-Gomez is
mandatory and nonwaivable. In his view, any time a crimi-
nal defendant is entitled to an evidentiary hearing under
Moya-Gomez, the district court must hold such a hearing on
its own initiative even in the absence of a request from the
defendant. Mr. Kielar offers no reason why any value pro-
tected by the Due Process Clause would require a mandato-
ry hearing in this context. Rather, he merely contends that
our decision in Moya-Gomez mandates this result.
    This argument is without merit. The defendant in Moya-
Gomez specifically requested a pretrial evidentiary hearing.
See 860 F.2d at 717. Nowhere in our opinion did we state or
suggest that the due process right that we acknowledged
was immune from the ordinary rules of waiver. “Constitu-
tional rights like other rights can be waived, provided that
the waiver is knowing and intelligent, as it was here.” United
No. 14-1390                                                                13

States v. Barnett, 415 F.3d 690, 691 (7th Cir. 2005). We there-
fore consider the issue waived.
    Even if this objection had been preserved, Mr. Kielar has
not presented sufficient evidence to demonstrate a bona fide
need for the assets at issue. He has offered no documentary
evidence, other than an unsubstantiated affidavit, to demon-
strate that the restrained assets were needed to conduct his
defense. In Moya-Gomez, we stressed that the right to a hear-
ing was “very limited” and required as a prerequisite that
“the district court find[] that the defendant does not have
other assets from which” he could pay for his defense. 860
F.2d at 730. Mr. Kielar’s one-and-a-half-page affidavit does
not provide enough information, much less enough reliable
information, to allow the district court to make this finding.
See Kirschenbaum, 156 F.3d at 792. Accordingly, even if we
were to presume that Mr. Kielar had preserved this objec-
tion, he still would not have been entitled to an evidentiary
hearing. 19



19 In his opening brief, Mr. Kielar offers a secondary argument concern-
ing his right to a post-indictment hearing on the pretrial restraint of his
assets. He contends that, regardless of his right to counsel of choice, he
nonetheless has a “general right” to a post-indictment, pretrial hearing
before being deprived of his property.
     This issue need not detain us long. Because Mr. Kielar did not raise
this issue before the district court, our review is for plain error. See Unit-
ed States v. Borostowski, 775 F.3d 851, 865 (7th Cir. 2014). “An error is
plain if it is clear or obvious.” Id. Here, Mr. Kielar has acknowledged that
whether the Due Process Clause requires a hearing in this context is an
“open question.” Appellant’s Br. 18 (internal quotation marks omitted).
Because any error, therefore, was not obvious, the plain error standard
has not been met. See Borostowski, 775 F.3d at 865.
14                                               No. 14-1390

                             B.
   We turn now to Mr. Kielar’s contention that the district
court impermissibly limited his cross-examination of
Dr. Barros.


                             1.
    Dr. Barros was one of the Government’s key witnesses at
trial. Prior to trial, the Government had produced records
showing that the Illinois Department of Public Aid (“IDPA”)
had recommended that Dr. Barros be terminated from par-
ticipating in IDPA’s Medical Assistance Program, which
consisted of Medicaid and other associated programs.
Among the reasons cited for Dr. Barros’s termination were
that he (1) had failed to obtain and document adequately pa-
tient histories and physical examinations and (2) had pre-
scribed medications without appropriate indications.
    In July 2013, the Government filed a motion in limine in
which it sought two limitations on the cross-examination of
Dr. Barros. First, it wanted to restrict any examination con-
cerning his termination from the IDPA program to the sole
ground of his recordkeeping. Second, it requested that cross-
examination on Dr. Barros’s recordkeeping be permitted on-
ly if the Government sought to introduce his records. In the
Government’s view, the other grounds for Dr. Barros’s ter-
mination were not probative of his character for truthfulness
but rather only went to his qualifications and competency as
a physician. In response, Mr. Kielar submitted that he should
be able to cross-examine Dr. Barros about all of the grounds
for termination from these programs because the infor-
No. 14-1390                                                15

mation was “relevant to show bias and self-interest in falsely
testifying that he did not prescribe Procrit in this case.” 20
    The district court denied in part and granted in part the
Government’s motion in limine. It precluded the introduc-
tion of extrinsic evidence if that evidence was intended sole-
ly to impeach Dr. Barros with regard to his character for
truthfulness. The court, however, “decline[d] to categorically
bar any cross-examination of [Dr. Barros] concerning the
IDPA recommendations,” noting that some of Mr. Kielar’s
“proposed lines of cross-examination may demonstrate bias
or self-interest on the part of [Dr. Barros].” 21
   On the first day of trial, the Government and defense
counsel informed the district court that they had “worked
out a solution” in which Dr. Barros would “testify that he
was terminated from Medicare and Medicaid in the early
2000–2001 time period” “and then that [would] be the end of
the issue as far as defense counsel and the government
[were] concerned.” 22
   When asked by the district court whether this compro-
mise would “essentially substitute” for any use of the IDPA
recommendation to impeach Dr. Barros, defense counsel re-
sponded, “We believe it will, Judge.” 23
   On direct examination, Dr. Barros testified that he had
never written a prescription for Procrit and that all of the


20   R.100 at 6.
21   R.107 at 5–6.
22   R.151 at 2.
23   Id. at 3.
16                                                No. 14-1390

prescriptions submitted under his name to BCBS and UFCW
contained forged signatures. He further testified that he was
terminated as a provider by Medicaid in 2000 and Medicare
in 2001.
    On cross-examination, defense counsel asked Dr. Barros
a series of questions about these terminations. At that point,
the Government objected. At a sidebar, it stated its under-
standing that defense counsel had agreed not to cross-
examine Dr. Barros on this topic. Defense counsel replied
that he had “never agreed not to ask any questions on this
issue.” 24 The court then inquired whether this was defense
counsel’s last question on the topic. Counsel responded that
all he wanted to do was to clarify the dates when Dr. Barros
was terminated from Medicaid as opposed to Medicare be-
cause he believed that the doctor had confused those dates
during his direct testimony. The court then stated, “How
about one last question, all it would establish is that as of
2001 he could no longer submit whatever it is, Medicare to
the state or Medicaid to the federal or whatever the right
way to go and just tie up and then move on. Fair enough?” 25
    Defense counsel did not object to this proposed solution.
Upon resuming his cross-examination, defense counsel clari-
fied the correct dates of Dr. Barros’s termination and moved
on to another line of questioning.




24   R.153 at 29.
25   Id. at 30.
No. 14-1390                                                   17

                               2.
    Mr. Kielar now contends that, by limiting his cross-
examination of Dr. Barros, the district court violated both
Federal Rule of Evidence Rule 608(b) as well as his right to
confrontation guaranteed by the Sixth Amendment. He con-
tends that the district court should not have prevented him
from further inquiring about the doctor’s termination from
Medicare and Medicaid. In his view, further inquiry into the
circumstances of the doctor’s termination was necessary to
show that Dr. Barros had a motive to “falsely testify[] that he
did not prescribe Procrit,” so as to “maintain[] his medical
license” and “regain[] eligibility for Medicaid.” 26
    Before proceeding to the merits of Mr. Kielar’s argument,
we first must address the Government’s contention that
Mr. Kielar waived, or at least forfeited, this objection by fail-
ing to raise it before the district court. “Waiver is the inten-
tional relinquishment of a known right, whereas forfeiture is
the failure to timely assert a right.” Rodriguez-Gomez, 608
F.3d at 972. “Forfeited errors may still be reviewed for plain
error, while waived errors are extinguished and cannot be
reviewed on appeal.” United States v. Berg, 714 F.3d 490, 494
n.1 (7th Cir. 2013) (alterations omitted) (internal quotation
marks omitted).
    Here, the Government first points out that, other than
precluding the admission of extrinsic impeachment evidence
against Dr. Barros (which Mr. Kielar does not challenge), the
district court never restricted Mr. Kielar’s right to cross-
examine Dr. Barros about his termination from Medicare or
Medicaid, or any other issue for that matter. Thus, the only

26   Appellant’s Br. 24.
18                                                No. 14-1390

reason why these questions were not asked, the Government
submits, was because “defendant’s trial counsel made the
strategic decision not to ask [them].” 27
    The Government’s assessment is correct. As the record
clearly demonstrates, Mr. Kielar reached an agreement with
the Government about how the parties would handle
Dr. Barros’s termination from Medicare and Medicaid.
When the Government objected that defense counsel’s cross-
examination of Dr. Barros was treading beyond the scope of
that agreement, the district court merely asked defense
counsel whether this was his last question on the matter. In
response, defense counsel stated that all he wanted to do
was clarify the dates on which Dr. Barros was terminated
from Medicaid as opposed to Medicare, because he believed
that the witness had confused those dates during his direct
examination. The court allowed defense counsel to clarify
this issue, suggesting that he “tie it up” in “one last ques-
tion” “and then move on.” 28 Notably, the court concluded its
suggestion by asking the parties, “Fair enough?”, to which
defense counsel expressed no objection. 29 In light of the par-
ties’ earlier acknowledgement that they had “worked out a
solution” in which Dr. Barros would “testify that he was
terminated from Medicare and Medicaid in the early 2000–
2001 time period” and “then that [would] be the end of the
issue,” 30 defense counsel’s decision not to object to the
court’s proposed solution, or to otherwise attempt to further

27   Appellee’s Br. 41.
28   R.153 at 30.
29   Id.
30   R.151 at 2.
No. 14-1390                                                               19

question Dr. Barros on this issue, was intentional. Accord-
ingly, we conclude that Mr. Kielar has waived any objection
concerning this issue. 31
     In any event, even if the district court had precluded
Mr. Kielar from questioning Dr. Barros about his termination
from Medicare and Medicaid, that decision would not have
constituted reversible error under either Rule 608(b) or the
Confrontation Clause. Rule 608(b) bars the admission of ex-
trinsic evidence “to prove specific instances of a witness’s
conduct in order to attack or support the witness’s character
for truthfulness.” Fed. R. Evid. 608(b). Under this rule, how-
ever, a district court may permit, in its discretion, a party to
cross-examine a witness about such prior conduct so long as
it is probative of the witness’s character for truthfulness. Id.
Rule 608(b) operates subject to the limitations imposed by
the Confrontation Clause of the Sixth Amendment, which
protects the right of a criminal defendant “to be confronted
with the witnesses against him.” U.S. Const. amend. VI.
    As a general matter, we review a district court’s limita-
tion on the scope of cross-examination for abuse of discre-
tion. United States v. Sasson, 62 F.3d 874, 882 (7th Cir. 1995).

31 See United States v. Cooper, 243 F.3d 411, 418 (7th Cir. 2001) (holding
“that a defendant’s attorney can waive his client’s Sixth Amendment
confrontation right so long as the defendant does not dissent from his
attorney’s decision, and so long as it can be said that the attorney’s deci-
sion was a legitimate trial tactic or part of a prudent trial strategy” (in-
ternal quotation marks omitted)); see also United States v. Donelli, 747 F.3d
936, 939, 941 (7th Cir. 2014) (concluding that a defendant waived any
objection concerning the district court’s failure to consider adequately
his mitigation arguments at sentencing by not raising that objection
when the court asked the parties “whether they had any objection to the
sentence or required ‘any further elaboration’ of the judge’s reasons”).
20                                                  No. 14-1390

Where, however, a limitation “directly implicates the core
values of the Confrontation Clause,” our review is de novo.
United States v. Recendiz, 557 F.3d 511, 530 (7th Cir. 2009) (in-
ternal quotation marks omitted). In determining the appro-
priate standard of review, it is important, therefore, to “dis-
tinguish between the core values of the confrontation right
and more peripheral concerns which remain within the am-
bit of the trial judge’s discretion.” United States v. Degraffen-
ried, 339 F.3d 576, 581 (7th Cir. 2003) (quoting United States v.
Saunders, 973 F.2d 1354, 1358 (7th Cir. 1992)).
    It is well established that “[e]xposing witness bias lies
within the protected core of the Confrontation Clause.” Unit-
ed States v. Sanders, 708 F.3d 976, 990 (7th Cir. 2013) (internal
quotation marks omitted). We also have recognized, howev-
er, that the constitutional guarantee is limited to the oppor-
tunity to expose the bias: “a limitation on cross-examination
implicates the core of the Confrontation Clause when the de-
fense is completely forbidden from exposing the witness’s
bias.” Id. (internal quotation marks omitted). “So long as the
accused is given the opportunity to expose bias, further cross
examination is at the discretion of the district court.” United
States v. Smith, 308 F.3d 726, 738 (7th Cir. 2002); see also Re-
cendiz, 557 F.3d at 530 (“[O]nce a trial court permits a de-
fendant to expose a witness’s motivation, it is of peripheral
concern to the Sixth Amendment how much opportunity de-
fense counsel gets to hammer that point home to the jury.”
(internal quotation marks omitted)).
   In this case, the fact that Dr. Barros was terminated from
participating in Medicare and Medicaid was exposed to the
jury; both the Government and defense counsel questioned
the doctor on this topic. Thus, because Mr. Kielar was “given
No. 14-1390                                                          21

the opportunity to expose [this potential ground for] bias,
further cross examination [was] at the discretion of the dis-
trict court.” Smith, 308 F.3d at 738. A district court does not
abuse its discretion in this context so long as “the jury had
sufficient information to make a discriminating appraisal of
the witness’s motives and biases.” Recendiz, 557 F.3d at 530
(internal quotation marks omitted). Here, the fact of
Dr. Barros’s termination alone gave the jury enough infor-
mation to appraise the witness’s motive to lie. Mr. Kielar’s
counsel could well have argued forcibly to the jury that
Dr. Barros’s removal from the government programs gave
him a strong motive to deny writing the prescriptions in
question because any such admission might have resulted in
further problems with federal or state regulatory authorities.
Indeed, an examination of the transcript at closing argument
indicates that his counsel made some attempt to do so. 32 In
any event, assuming for the sake of argument that this issue
was not waived, it is clear that the cross-examination that
did take place gave defense counsel enough opportunity to
make his point.
   Therefore, assuming the district court had restricted
Mr. Kielar’s cross-examination of Dr. Barros, that limitation
would not have been an abuse of discretion. See Sanders, 708
F.3d at 991 (noting that just because “[t]he jury might not
have possessed all the information [the defendant] wanted it
to have” does not mean that the jury lacked “sufficient in-
formation to evaluate [the witness’s] testimony”). Accord-


32See R.154 at 148 (“And Dr. Barros. [The prosecutor] also asked what
does Dr. Barros have to gain. Well, what Dr. Barros has to gain is he is
not sitting right here.”).
22                                                No. 14-1390

ingly, waiver aside, Mr. Kielar’s evidentiary challenge fails
on its merits.


                              C.
    Finally, Mr. Kielar contends that the district court erred
by preventing him from calling Fernando Perez as a defense
witness. We review the district court’s evidentiary rulings
for abuse of discretion. United States v. Khan, 771 F.3d 367,
377 (7th Cir. 2014).


                              1.
    Prior to trial, the Government listed Fernando Perez as a
potential witness. Perez, a former patient of Dr. Barros and a
customer at the Cartagena Pharmacy, was slated to testify
that Dr. Barros never had prescribed Procrit for him. When
the Government later elected not to call Perez, defense coun-
sel informed the Government of his intent to call the witness.
In response, the Government moved to preclude Mr. Kielar
from calling Perez. When asked by the district court why he
intended to call Perez, defense counsel explained that he in-
tended to impeach the witness’s credibility. In particular, de-
fense counsel stated that, when called, Perez would “deny
that he was ever prescribed Procrit, [or] that he ever got any
Procrit,” and that defense counsel would then impeach the
witness by asking whether he had stolen his cousin’s identi-
ty and whether he was an illegal alien (both of which de-
fense counsel believed were true). 33


33   R.153 at 126.
No. 14-1390                                                    23

    The Government objected to this proffer, asserting that
defense counsel was “calling [Perez] solely for the purpose
of impeaching him.” 34 In response, the court asked defense
counsel whether “that[ was] all there [was] to it,” to which
defense counsel responded, “That’s all there is to it,
Judge.” 35
    When asked whether he intended to ask Perez any other
questions, defense counsel responded that he also might ask
the following: “The government told you that they were go-
ing to call you as a witness and then sometime during the
trial you were—on a certain date you were interviewed and
the government told you that they were not going to call you
as a witness.” 36
    The next day, the court granted the Government’s oral
motion in limine. Relying on our decision in United States v.
Giles, 246 F.3d 966 (7th Cir. 2001), the district court ruled that
Mr. Kielar’s counsel could not call Perez as a defense witness
because his only reason for doing so was to impeach him.


                                2.
    It is well established that “a party may not call a witness
for the sole purpose of impeaching him.” Id. at 974. In Giles,
as here, a defendant sought to call as a witness an individual
who was slated to testify for the Government but whom the
Government chose not to call at trial. Id. We affirmed the dis-


34   Id.
35   Id. at 127.
36   Id.
24                                                    No. 14-1390

trict court’s decision to preclude the defendant from calling
this individual, concluding that the defendant’s “true de-
fense reason…for wanting to put [this witness] on the stand
was to expose his warts to the jury and float the inference
that the [Government] should not play footsie with a sleaze-
ball.” Id.
    Mr. Kielar attempts to avoid Giles’s clear holding by as-
serting that impeachment was not the “only reason” that he
wanted to call Perez as a witness. 37 In particular, he contends
that although “trial counsel believed Mr. Perez would likely
testify that he was never prescribed Procrit by
Dr. Barros…[,] trial counsel was willing to make the tactical
decision that under oath Mr. Perez may testify that he was
prescribed Procrit.” 38
    Mr. Kielar never communicated to the district court this
reason for permitting Perez’s testimony. We therefore refuse
to consider this theory of admissibility for the first time on
appeal. See United States v. Biesiadecki, 933 F.2d 539, 544 n.1
(7th Cir. 1991); United States v. Marrera, 768 F.2d 201, 209 (7th
Cir. 1985); see also Stephens v. Miller, 13 F.3d 998, 1008 n.5 (7th
Cir. 1994) (en banc) (Rovner, J., concurring) (“A defendant
cannot advance one reason for admitting evidence during
trial and then advance a wholly separate basis for admis-
sion…on appeal. An evidentiary rationale not raised before
the trial judge at the time of ruling is waived.”). Because
Mr. Kielar’s only proffered reason for calling Perez as a de-
fense witness was to impeach him, we conclude that the dis-


37   Appellant’s Br. 26 (emphasis in original).
38   Id. at 26–27 (emphasis in original).
No. 14-1390                                                25

trict court’s decision to grant the Government’s motion in
limine was proper.


                        Conclusion
   The judgment of the district court is affirmed.
                                                     AFFIRMED
