United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
                                   ___________

                                   No. 08-3775
                                   ___________

United States of America,               *
                                        *
             Appellee,                  *
                                        * Appeal from the United
      v.                                * States District Court for the
                                        * Northern District of Iowa.
Gene Leonard Smith,                     *
                                        *
             Appellant.                 *
                                   ___________

                             Submitted: June 11, 2009
                                Filed: July 24, 2009
                                 ___________

Before MELLOY, BEAM, and COLLOTON, Circuit Judges.
                           ___________

MELLOY, Circuit Judge.

       Gene Leonard Smith pleaded guilty to conspiracy to distribute and possess with
intent to distribute five-hundred grams or more of a methamphetamine mixture, in
violation of 21 U.S.C. §§ 841(a)(1), 841(b)(1)(A), and 846; the knowing or intentional
use of a person under eighteen years of age in a drug conspiracy, in violation of 21
U.S.C. § 861(a)(1); and knowingly possessing a firearm in the furtherance of a drug-
trafficking crime, in violation of 18 U.S.C. § 924(c)(1)(A). The district court1
sentenced Smith to the mandatory statutory minimum of life imprisonment for the

      1
       The Honorable Mark W. Bennett, United States District Judge for the
Northern District of Iowa.
drug offenses given Smith’s two prior drug felonies, see 21 U.S.C. §§ 841(b)(1)(A)
and 851, and a sixty-month consecutive sentence for the use of a firearm in
furtherance of the drug crimes. See 18 U.S.C. § 924(a)(1). Smith appeals, claiming
that the district court erred in refusing to compel the government to file a motion for
downward departure pursuant to 18 U.S.C. § 3553(e). We affirm.

                                           I.

        As part of his plea agreement, Smith agreed to cooperate with law enforcement
in the investigation and prosecution of his co-conspirators. The agreement explicitly
provided that if the government, in its “sole discretion,” concluded that Smith
provided “substantial assistance” in the investigation and prosecution of other persons
connected to the drug conspiracy, then it “may,” but would “not be required to,” move
for a downward departure under § 3553(e) and/or U.S. Sentencing Guidelines §
5K1.1. See 18 U.S.C. § 3553(e) (“Upon motion of the Government,” the district
court may depart from the statutory minimum sentence “to reflect a defendant’s
substantial assistance in the investigation or prosecution of another person.”); USSG
§ 5K1.1 (authorizing a departure from the Guidelines sentence “[u]pon motion of the
government stating that the defendant has provided substantial assistance in the
investigation or prosecution of another person”).

       In accordance with his plea, law-enforcement officers debriefed Smith for two
days. He took and passed a polygraph test when officers raised questions about his
truthfulness. On July 3, 2008, Smith testified for the government at co-defendant
Leodan Vasquez’s sentencing hearing. Smith also testified as a prosecution witness
during the trial of co-defendant Jose Juan Islas-Bravo on July 23, 2008. At that
proceeding, Smith appears to have testified in accordance with the proffer he made in
his debriefing sessions. The government did not introduce additional evidence to
corroborate Smith’s testimony. When addressing Vasquez’s motion to acquit,
however, the district court expressed doubts about Smith’s credibility as a witness in
that case, stating that it had “strong feelings” about Smith’s “lack of credibility.” The

                                          -2-
district court also appeared concerned over whether Islas-Bravo’s conviction could be
based on Smith’s statements alone. Smith claims that instead of remaining “mute” in
the face of the district court’s statements, the government should have mentioned
evidence corroborating his story so as to assure the district court that Smith was a
reliable witness. Ultimately, the jury acquitted Islas-Bravo of the criminal count for
which Smith’s testimony had provided the only evidence.

        Despite Smith’s debriefing and testimony, the government declined to move for
a lesser sentence under either § 3553(e) or § 5K1.1. Smith filed a motion to compel
the government to file a substantial-assistance motion under § 3553(e), claiming that
its failure to do so had violated Smith’s plea agreement. At sentencing, the district
court found that “because the plea agreement broadly reserves the decision to make
a substantial assistance motion [to] the sole discretion of the U.S. Attorney’s Office,”
there was no breach of the plea agreement. On appeal, Smith contends that the district
court erred in denying his motion to compel, alleging that the government’s refusal
to file a motion “was based upon an unconstitutional motive, was irrational, and was
made in bad faith and for the improper purpose of dictating the length of Mr. Smith’s
sentence.” We review the district court’s denial of a motion to compel for abuse of
discretion. United States v. Perez, 

, 1138 (8th Cir. 2008).

                                          II.

       Unless a plea agreement provides to the contrary, see United States v. Holbdy,

, 913 (8th Cir. 2007), “[b]oth § 3553(e) and § 5K1.1 give ‘the
Government a power, not a duty, to file a motion when a defendant has substantially
assisted’” in the prosecution or investigation of other persons involved in criminal
activity. Perez, 526 F.3d at 1138 (quoting Wade v. United States, 

, 185
(1992)). The “otherwise broad discretion of the government to file a motion for
substantial assistance,” United States v. Davis, 

, 676 (8th Cir. 2005), is
tempered when a defendant makes a “substantial threshold showing that the
government’s refusal to make a substantial assistance motion was premised on an

                                          -3-
improper motive.” Perez, 526 F.3d at 1138 (quotations omitted). “This threshold
showing requires more than the presentation of evidence of substantial assistance and
general allegations of improper motive because we presume a prosecutor has properly
discharged her duties absent clear evidence to the contrary.” Id. (quotation omitted).
“A district court may review the government’s refusal to make a substantial assistance
motion . . . if such refusal (1) was prompted by an unconstitutional motive, such as the
defendant’s race or religion; or (2) was not rationally related to a legitimate
government interest.” Id. (quotation omitted).

       As articulated at Smith’s sentencing hearing, the government’s decision not to
move for downward departure was based on a variety of factors relating to “the
significance of the defendant’s assistance.” The government expressed concerns
about the reliability of Smith’s information and his credibility generally, as did the
district court in Islas-Bravo’s trial. Additionally, the government believed that given
his lack of credibility, Smith was an ineffective prosecution witness. This was
supported by the fact that the jury acquitted Islas-Bravo on the conspiracy charge
about which Smith testified. Given this “outcome[]” and his performance on cross-
examination, the government concluded that Smith was “pretty much useless in the
future.” In addition to his ineffectiveness as a witness, the government pointed out
that Smith’s role in the Vasquez sentencing was minimal: he testified about the price
of drugs and Vasquez’s role in the conspiracy. This information provided evidence
for the application of a sentencing enhancement.

       As further support for its refusal to make the motion, the government noted the
timing of Smith’s cooperation. Smith began cooperating with law enforcement after
the investigation into the conspiracy had already ended. By the time the government
debriefed him and attempted to verify his credibility via polygraph, Smith was only
available to testify in the Vasquez sentencing hearing and the Islas-Bravo trial. The
government also highlighted as a reason to refrain from moving that Smith had not



                                          -4-
engaged in “any active” cooperation or investigation on the government’s behalf
because he was incarcerated.

        In response to the government’s justifications for not filing a motion, Smith has
presented no evidence that the decision was based on an unconstitutional motive, such
as his race or his religion. See, e.g., United States v. Moeller, 

, 712 (8th
Cir. 2004) (finding no unconstitutional motive when “the prosecutor explicitly stated
that the government’s decision not to file a § 3553(e) motion was based upon the
cooperation [the defendant] provided” and nothing in the record contradicted that
claim (quotation and alteration omitted)).

       Smith has also not presented evidence that the government’s refusal to file a
substantial-assistance motion was not rationally related to a legitimate end. See Wade,
504 U.S. at 187 (“The Government’s decision not to move [for a motion] may have
been based not on a failure to acknowledge or appreciate [the defendant’s] help, but
simply on its rational assessment of the cost and benefit that would flow from
moving.”). Smith argues that the government considered factors other than his
assistance when determining whether to make the motion and that this was improper.
Specifically, he claims that the government refused to make the motion because it
hoped to dictate the length of Smith’s sentence and limit the sentencing court’s
discretion. “A defendant’s assistance is the only permissible basis for the government
to exercise or refuse to exercise its power under § 3553(e).” United States v.
Freemont, 

, 888 (8th Cir. 2008). And “[t]he desire to dictate the length
of a defendant’s sentence for reasons other than his or her substantial assistance is not
a permissible basis for exercising the government’s power under § 3553(e).” United
States v. Stockdall, 

, 1261 (8th Cir. 1995). But, as outlined above, there
is no evidence to indicate that the government based its decision not to move on
anything other than Smith’s assistance, or lack thereof. We recognize that “[t]he
government’s refusal to file a § 3553(e) or § 5K1.1 motion always has the effect of
limiting the sentencing court’s discretion. But so long as the government is exercising


                                          -5-
the statutory power conferred by those laws and its action is not based on an
unconstitutional motive, its refusal to file the motion is unreviewable.” Moeller, 383
F.3d at 713.

       Smith also claims that “the government . . . based its decision . . . on a factor
other than the substantial assistance . . . because [it relied on the fact that] the trial
court had discredited [Smith’s] testimony” in deciding not to move. Contrary to
Smith’s claim, however, questions about the credibility of a defendant in a case where
the government assistance involves an activity such as providing testimony—whether
expressed by the government or a presiding judge—“do relate to the quality of . . .
assistance.” See Perez, 526 F.3d at 1139 n.2. As such, it is not an improper basis
upon which to determine whether to file a motion for substantial assistance. Id.

       Smith’s final claim of improper motive is that the government refused to file
the motion “in bad faith” because it was being a “sore loser[]” following its inability
to obtain a conspiracy conviction in the Islas-Bravo trial. We conclude that Smith has
only set forth “‘generalized allegations of improper motive,’” which are insufficient
to make the threshold showing required for relief. See Perez, 526 F.3d at 1138
(quoting Wade, 504 U.S. at 186).

       In conclusion, because we hold that Smith has failed to meet the threshold
showing of improper motive, the district court did not abuse its discretion in refusing
to compel the government to file a § 3553(e) motion. See id. at 1139; see also
Moeller, 383 F.3d at 713 (“When the government ties its refusal to make a § 3553(e)
motion to the defendant’s substantial assistance, or lack thereof, and the defendant
fails to make a substantial threshold showing of improper motive, an evidentiary
hearing is not warranted.”).




                                           -6-
                                         III.

       Finally, Smith argues that the doctrine of judicial estoppel should have
prevented the government from arguing at his November 6, 2008 sentencing that
Smith did not provide substantial assistance. Smith claims that the government’s
position during his sentencing was “clearly inconsistent” with its position in the
October 16, 2008 appellate brief it submitted to this court in co-conspirator Vasquez’s
sentencing appeal. In that brief, the government argued “that the district court had
committed no error by relying upon [Smith’s testimony] in imposing a three-level
sentencing enhancement” at Vasquez’s sentencing hearing. We disagree with Smith.

       Judicial estoppel is an equitable remedy fashioned “to protect the integrity of
the judicial process by prohibiting parties from deliberately changing positions
according to the exigencies of the moment.” New Hampshire v. Maine, 

, 749–50 (2001) (internal citations and quotations omitted). In order to prevail on
a claim of judicial estoppel, Smith must first establish that the government’s position
at his sentencing was “‘clearly inconsistent with its earlier position’” during
Vasquez’s appeal. See Stallings v. Hussmann Corp., 

, 1047 (8th Cir.
2006) (quoting New Hampshire, 532 U.S. at 750). Smith has failed to meet this basic
requirement. There is nothing “clearly inconsistent” with the government’s position
that Smith did not warrant a § 3553(e) motion and its position during the Vasquez
appeal that Smith’s testimony was reliable enough to serve as the basis of a sentencing
enhancement. The government’s determination of whether Smith provided substantial
assistance and merited the motion was based on “the significance of the defendant’s
assistance” in both the Vasquez and Islas-Bravo trials. As previously highlighted, the
government’s decision to move includes consideration of many factors in addition to
Smith’s credibility. Smith’s claim thus fails.




                                         -7-
                               IV.

For the foregoing reasons, we affirm the judgment of the district court.
               ______________________________




                               -8-