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

No. 01-4349
UNITED STATES OF AMERICA,
                                              Plaintiff-Appellee,
                               v.

DWIGHT A. GRAHAM,
                                          Defendant-Appellant.
                         ____________
           Appeal from the United States District Court
                for the Central District of Illinois.
           No. 01-CR-20025—Jeanne E. Scott, Judge.
                         ____________
   ARGUED NOVEMBER 8, 2002—DECIDED JANUARY 8, 2003
                    ____________


  Before POSNER, ROVNER, and WILLIAMS, Circuit Judges.
  WILLIAMS, Circuit Judge. A jury found Dwight A. Gra-
ham guilty of distributing 50 grams or more of cocaine
base, in violation of 21 U.S.C. §§ 841(a)(1) and (b)(1)(A)(iii).
On appeal, Graham challenges the sufficiency of the evi-
dence, statements made by the prosecutor during closing
arguments, and the district court’s consideration of his
prior conviction in sentencing him to a mandatory mini-
mum sentence of twenty years’ imprisonment. For the
following reasons, we affirm the district court’s judgment
and uphold Graham’s conviction and sentence.
2                                              No. 01-4349

                    I. BACKGROUND
  On March 8, 2001, a federal grand jury indicted Graham
for distributing 50 grams or more of cocaine base in vio-
lation of 21 U.S.C. §§ 841(a)(1) and (b)(1)(A)(iii). The in-
dictment concerned an August 24, 2000, drug transaction
between Graham and Joe Rapier, a confidential source
working with the Vermilion County Metropolitan Enforce-
ment Group (“VMEG”), a multi-jurisdictional drug task
force. Because Graham challenges the sufficiency of the
evidence supporting his conviction, we review the evi-
dence introduced at trial.


A. Evidence presented during trial
   Rapier and Graham were familiar with one another and
had engaged in drug transactions in the past. Rapier agreed
to cooperate with law enforcement after he was appre-
hended while purchasing and selling crack cocaine. Late
on the evening of August 23, 2000, VMEG agents out-
fitted Rapier with several electronic surveillance devices,
including a digital cassette recorder to tape his conver-
sations with Graham and a radio frequency transmit-
ter to permit the agents to monitor his interactions with
Graham. Shortly past midnight on August 24, 2000, Rapier
phoned Graham and asked to purchase two ounces of
crack cocaine. Graham told Rapier to meet him at Garfield
Park, where several agents followed Rapier to maintain
audio monitoring and visual contact.
  The two conversed in Garfield Park for several minutes,
during which time Rapier repeated his request for two
ounces of cocaine, and Graham told Rapier to meet him
at his uncle’s house nearby. Rapier proceeded to Graham’s
uncle’s house, followed by VMEG agents. He waited there
for between 15 and 20 minutes, calling Graham in the
meantime to inquire when he would arrive.
No. 01-4349                                                3

  Upon arriving, Graham entered his uncle’s house and
then returned to Rapier, handing him two ounces of crack
cocaine in exchange for $1,800. During the tape-recorded
conversation, Rapier commented on the high quality of
the crack cocaine and attempted to bargain on the pur-
chase price. Graham told Rapier that he would soon “be
hollering at me,” meaning that Rapier would enjoy the
drugs so much that he would purchase more from Graham.
He also instructed Rapier to keep Graham’s drug dealing
a secret.
  When the two parted, agents followed Graham’s ve-
hicle, a 1970 Cadillac coupe with distinctive lights in the
tailfins, to a nearby gas station, where they recorded
the car’s license plate. The agents testified that an inves-
tigation of the Cadillac’s license plate number revealed
that Graham had purchased the vehicle in February 2000
for $3,000 cash. A separate group of agents met Rapier
at a designated location and confiscated the crack cocaine
he had obtained from Graham. Illinois State Police fo-
rensic officers determined that the substance contained
cocaine base and weighed 56.5 grams.
  At trial the jury heard the tape-recorded interactions
as well as testimony from law enforcement personnel who
followed Rapier throughout the evening. Rapier and law
enforcement officials testified that the second voice heard
on the tape recordings presented was Graham’s, while
several of Graham’s relatives attested that they could
not recognize the voice. The jury also heard evidence that
calls made to Rapier’s cell phone were placed from a cell
phone registered to Graham’s fiancee. While registered
to his fiancee, the cell phone’s call patterns closely resem-
bled Graham’s work schedule.
 Graham presented alibi evidence that after leaving
work at 11:30 p.m. on August 23, 2000, he and Terrence
Parker, his coworker and friend, drove ten minutes to a
4                                            No. 01-4349

local liquor store. Graham and Parker, driving in a 1970
Cadillac coupe, proceeded to the home of Graham’s fian-
cee, Sheila Walker. Walker testified that the two stayed
at her house for only about ten minutes. Graham and Park-
er claimed that they left Walker’s home at approximately
12:30 a.m., and then drove twenty minutes to Parker’s
house, where they socialized until 2 a.m. Graham asserted
that he was never in or near Garfield Park on the even-
ing of August 23 and the morning of August 24, 2000. He
also claimed that he was never in the gas station where
law enforcement personnel claimed to have observed his
vehicle and recorded his license plates. Graham further
attacked Rapier’s credibility. Finally, he denied using
Walker’s cell phone that evening.
  The jury convicted Graham following a three-day trial.
In his post-trial motion, Graham alleged that the gov-
ernment failed to meet its burden in proving his guilt
beyond a reasonable doubt and that the prosecutor had
made improper statements during closing arguments. In
a written order, the district court found that “[c]learly
there was evidence upon which the jury could have rea-
sonably relied in finding the Defendant guilty beyond a
reasonable doubt” and that the prosecutor’s remarks
were not improper.


B. Sentencing
   Because Graham had a prior drug-related felony con-
viction and his current offense involved greater than 50
grams of crack cocaine, he was subject to a mandatory
minimum sentence of twenty years’ imprisonment and
a maximum of life imprisonment. Graham argued unsuc-
cessfully at sentencing that his prior state court felony
conviction could not be used in his sentencing because
he had been admitted to “first offender probation” under
Illinois state law. The district court sentenced Graham to
No. 01-4349                                              5

the minimum 240 months’ imprisonment, ten years’ super-
vised release, and a $100 special assessment.


                     II. ANALYSIS
A. Sufficiency of the evidence
  Graham argues that the government failed to carry its
burden at trial of proving his guilt beyond a reason-
able doubt. A party challenging the sufficiency of the evi-
dence supporting a jury conviction faces a steep uphill
battle. See United States v. Moore, 

, 1363
(7th Cir. 1999) (describing defendant’s burden as “nearly
insurmountable”); United States v. Gillespie, 

,
805 (7th Cir. 1992) (observing that “a defendant making
a sufficiency challenge bears a heavy burden”). He may
prevail only if, viewing the evidence in the light most
favorable to the government and deferring to the jury’s
credibility determinations, the record contains no evi-
dence from which the jury could find guilt beyond a rea-
sonable doubt. 

. We will uphold
the verdict when any juror could rationally have found
the crime’s essential elements were met beyond a reason-
able doubt. 

.
  To convict Graham, the government had to establish two
elements: (1) that he knowingly distributed 50 grams or
more of a mixture or substance containing cocaine base
and (2) that he knew that what he was distributing
was a controlled substance. 21 U.S.C. §§ 841(a)(1), (b)(1)
(A)(iii). We agree with the district court that there was
evidence upon which jurors reasonably could conclude
that Graham was guilty beyond a reasonable doubt. That
evidence included a tape recording of the transaction
between Graham and Rapier and records from Graham’s
fiancee’s cell phone showing conversations with Rapier.
Witnesses for the government identified the voice on
the tape as Graham’s, while witnesses for the defense tes-
6                                               No. 01-4349

tified that they could not recognize the voice. Law enforce-
ment officials testified that they observed Graham’s ve-
hicle, a 1970 Cadillac coupe with distinctive tailfin lights,
at the scene of the transaction. Furthermore, the tape re-
cording demonstrated that Rapier and Graham decided
that the actual transaction would occur at the home of
Graham’s uncle. This court cannot second-guess the jury’s
determination of which witnesses were credible and
which were not. United States v. Griffin, 

, 817
(7th Cir. 1999) (citing United States v. Alcantar, 

, 189 (7th Cir. 1996)). Therefore, we affirm the district
court’s finding that the evidence was sufficient to sup-
port the jury’s verdict.


B. Prosecutor’s statements during closing arguments
  Graham also challenges two statements made by the
prosecutor during closing arguments, asserting that the
remarks deprived him of a fair trial. This court follows
a two-step analysis in determining whether statements
made during closing arguments constitute prosecutorial
misconduct. United States v. Butler, 

, 254 (7th
Cir. 1995). First, we examine the disputed remarks to
determine whether they were proper. 

statements
were proper, then our study ends. 

statements
were improper, we examine them in light of the entire
record to see if they deprived the defendant of a fair trial.

second portion of the analysis, we consider:
(1) the nature and seriousness of the misconduct; (2) the
extent to which the comments were invited by the defense;
(3) the extent to which any prejudice was ameliorated
by the court’s instruction to the jury; (4) the defense’s
opportunity to counter any prejudice; and (5) the weight
of the evidence supporting the conviction. United States
v. Scott, 

, 740 (7th Cir. 2001) (citing United
States v. Amerson, 

, 686 (7th Cir. 1999)).
No. 01-4349                                                     7

  In the first challenged statement, the prosecutor referred
to the car observed in the August 24, 2000, drug transac-
tion as “Defendant’s Cadillac.”1 As Graham did not object
to this statement at trial, we review for plain error. See
United States v. Sandoval-Gomez, 

, 762 (7th
Cir. 2002); 

. Under this standard,
Graham must demonstrate not only that the prosecutor’s
remarks were improper and deprived him of a fair trial,
but that they also prejudiced him, i.e., that the trial’s
outcome would have been different had the remarks not
been made. See 

.
  Graham cannot meet the plain error standard because
the prosecutor’s statement was not improper. A prosecutor
may argue reasonable inferences from the evidence that
the jury heard. United States v. Adeniji, 

,
1029-30 (7th Cir. 2000); United States v. Ward, 

, 365 (7th Cir. 2000). The license plate number of the
Cadillac showed that Graham had purchased the vehicle.
Walker, Parker, and Graham himself admitted that he had
been driving the car on the morning of August 24, 2000.
Thus it is reasonable to infer that the Cadillac was Gra-
ham’s. As such, the prosecutor’s statement describing the
vehicle as “Defendant’s Cadillac” was not improper.
  The prosecutor’s second statement addressed challenges
by Graham to Rapier’s credibility.2 The prosecutor argued



1
  The prosecutor argued in closing that “Agent Johnson followed
that Cadillac, the Defendant’s Cadillac, and was able to obtain—
he radioed in the license plate number.”
2
  The prosecutor stated: “And remember this; as defense counsel
will certainly attack Mr. Rapier; it was the Defendant, not the
Government, who really chose Mr. Rapier as a witness in this
case. As Agent Shanks testified why they use confidential sources;
because criminals deal with criminals. And in this case it took
                                                    (continued...)
8                                               No. 01-4349

that it was Graham who had chosen Rapier as a witness
by selling drugs to him. Because “criminals deal with crim-
inals,” the prosecutor contended, confidential sources used
by law enforcement officers tend to have criminal histories.
Graham did object to this statement at trial, so we re-
view the issue for abuse of discretion. United States v.
Knox, 

, 1000 (7th Cir. 1995). When placed in the
context of the closing argument, the prosecutor’s com-
ment did not imply that Graham forced Rapier to testify;
rather, the prosecutor was emphasizing that by selling
drugs to Rapier, Graham had selected the government’s
witness. The comment did not improperly portray the
burden of proof.
  Even if this statement was improper, Graham cannot
establish that it deprived him of a fair trial. The district
court remedied any prejudice caused by the statement
with a curative instruction to the jury, explaining that
“Defendant had no obligation to present any evidence . . . it
would have been his constitutional right to remain si-
lent.” Moreover, Graham had an opportunity to address
the prosecutor’s statement in his own closing argument.
As discussed previously, the evidence supporting the con-
viction was substantial. For these reasons, we conclude
that the prosecutor’s statement did not deprive Graham
of a fair trial.


C. Consideration of Graham’s prior conviction in
   sentencing
 Finally, Graham argues that the district court erred
when it considered his prior drug conviction in determin-



2
  (...continued)
a Joe Rapier or someone like him to purchase drugs from the
Defendant, a person who the Defendant would sell to.”
No. 01-4349                                               9

ing the mandatory minimum sentence of twenty years’
imprisonment and maximum of life imprisonment. Sec-
tion 841(b)(1)(B) provides enhanced penalties for offen-
ders with one or more prior convictions for drug-related
felonies. 21 U.S.C. § 841(b)(1)(B). Graham was found guilty
of felony possession of a controlled substance in 1994,
and an Illinois court sentenced him to two years’ probation
under 720 Ill. Comp. Stat. 570/410. His probation was
discharged in March 1997. The district court applied
this prior conviction under § 841(b)(1)(B) in sentencing
Graham.
  Federal law, not state law, defines what is considered
a conviction for the purposes of § 841(b)(1)(B). United
States v. Gomez, 

, 930 (7th Cir. 1994). Under
federal law, a sentence of probation received according
to 720 Ill. Comp. Stat. 570/410 constitutes a conviction.
United States v. McAllister, 

, 1185 (7th Cir.
1994). Furthermore, the Supreme Court made clear in
Dickerson v. New Banner Institute, Inc., 

(1983), that expunction does not alter or remove the
existence of a prior conviction. 

Thus, the fact
that Graham received probation that was later discharged
does not alter the fact that he possesses a prior drug-
related felony conviction qualifying him for the enhance-
ment under § 841(b)(1)(B).
  Graham urges this court to overrule Dickerson. Contrary
to the assertions of Graham’s counsel during oral argu-
ment, our reluctance to overturn Dickerson comes not
from a lack of courage. We cannot simply overturn the
United States Supreme Court; rather, it is our obliga-
tion as an intermediate appellate court to follow Su-
preme Court precedent. United States v. Jackson, 

, 327 (7th Cir. 1987) (citing United States v. Bush,

, 861-62 (7th Cir. 1987)); United States ex
rel. Link v. Lane, 

, 1170 (7th Cir. 1987). We
therefore reject Graham’s argument and hold that the dis-
10                                            No. 01-4349

trict court did not err in considering his 1994 possession
offense a prior conviction for sentencing purposes under
§ 841(b)(1)(B).


                   III. CONCLUSION
  For the reasons stated above, we affirm the judgment
of the district court.
                                               AFFIRMED.

A true Copy:
      Teste:

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




                   USCA-02-C-0072—1-8-03