The principal question in this direct criminal appeal is whether, for Ex Post Facto Clause purposes, the government must apply the version of United States Sentencing Guideline § 5K1.1 that was in effect when a defendant attempted to provide substantial assistance to the authorities or the version that was in effect when the defendant committed the underlying criminal offense. We hold that the critical date in our retroactivity analysis under § 5K1.1 is when the cooperation was provided, rather than when the crime occurred. Accordingly, we affirm. 1
I.
The Defendant-Appellant, Joan Gerber (“Gerber”), pled guilty to interstate transportation in aid of racketeering enterprises, in violation of 18 U.S.C. § 1952, and money laundering, in violation of 18 U.S.C. § 1956. During the sentencing hearing, the government informed the court about Gerber’s extensive efforts to assist in the prosecution of other suspects. Indeed, the government explained that Gerber attended “numerous debriefings with [federal] agents, and hours, in fact days, of debriefings-” The government described Gerber as “open and candid with the information that she did possess” and as having made a “fairly strong effort” to assist. Gerber’s diligent efforts notwithstanding, the government declined to file a motion pursuant to United States Sentencing Guideline (“U.S.S.G.”) § 5K1.1 for a two-point reduction in Gerber’s base offense level for substantial assistance to authorities. The government concluded that Gerber’s “information did not rise to the level of a substantial assistance motion” because the information “was not sufficient for us to move on in any way, shape or form.”
The offenses to which Gerber pled guilty occurred in March and April 1989. At that time, § 5K1.1 provided that “[u]pon a motion of the government stating that the defendant has made a good faith effort to provide substantial assistance ..., the court may depart *95 from the guidelines.” U.S.S.G. § 5K1.1 (1988) (emphasis added). On November 1, 1989, well before the court conducted Gerber’s sentencing hearing, the Commission’s amendment to § 5K1.1 took effect. In place of the “good faith effort” language, the amended version provided that “[u]pon motion of the government stating that the defendant has provided substantial assistance ..., the court may depart from the guidelines.” U.S.S.G. § 5K1.1 (1989) (emphasis added). The government concedes that its decision not to file a downward departure motion for substantial assistance arose from its application of the amended version of § 5K1.1. Appee. Br. at 10. Gerber’s cooperation did not merit a substantial assistance motion, the government reasoned, because the test under the November 1989 amendment to § 5K1.1 is whether Gerber actually provided substantial assistance, not whether she engaged in a good faith effort to provide such assistance.
In this appeal, Gerber alleges that the government’s application of the amended version of § 5K1.1 violated the Ex Post Facto Clause of Article I of the United States Constitution. 2 The government responds that the Ex Post Facto Clause was not implicated because the amendment to § 5K1.1 merely clarified the existing provision and in no way altered the government’s discretion to file a downward departure motion for substantial assistance. 3
II.
Although § 5K1.1 “gives the government a power, not a duty, to file a [downward departure] motion” for substantial assistance, we exercise jurisdiction to review alleged constitutional infirmities arising from the prosecutor’s discretionary refusal to file a § 5K1.1 motion.
Wade v. United States,
— U.S. -, -,
Gerber neither objected to the presentence report nor requested the district court to conduct an evidentiary hearing to determine whether she was entitled to a downward departure for substantial assistance. We therefore must apply the plain error standard of review.
United States v. Saucedo,
The Supreme Court admonishes that the “plain-error exception to the contemporaneous-objection rule is to be ‘used sparingly, solely in those circumstances in which a miscarriage of justice would otherwise result.’ ”
United States v. Young,
III.
A sentencing court is generally required to' apply the Guidelines that are in effect on the date the defendant is sentenced.
United States v. Brunson,
“An ex post facto law is one that among other things (1) makes conduct criminal that was legal when done, or (2) inflicts greater punishment for an offense than the law existing when the offense was committed.”
United States v. Patzer,
Consistent with this analytical framework, we held in
Underwood
that the Ex Post Facto Clause prevented the court from applying the amended version of § 2Dl.l(b)(l) — which imposes a two-point upward adjustment for the possession of a firearm during the commission of a drug offense — that did not take effect until after the defendant committed the offense.
Underwood,
We have identified two principles underlying the Ex Post Facto Clause: “to restrain legislatures and courts from arbitrary and vindictive action and to prevent prosecution and punishment without fair warning.”
Devine v. New Mexico Dep’t of Corrections,
As noted, the government in the instant case concedes that it relied on the November 1989 amended version of § 5K1.1 in opting not to file a motion on behalf of Gerber for substantial assistance. The November 1989 amendment to § 5K1.1, in effect when Gerber was sentenced, markedly narrowed a defendant’s eligibility for such a motion by replacing the “good faith” standard with the “has provided substantial assistance” standard. U.S.S.G. § 5K1.1 (1989).
Nevertheless, the government contends that its application of the November 1989 version of § 5K1.1 did not implicate the Ex Post Facto Clause because the amendment constituted a clarification rather than a substantive change.
See Saucedo,
*97
However, we read the textual change to § 5K1.1 as a substantive amendment. It makes a substantive change in the standard that must be met before a defendant can become eligible for a downward departure for substantial assistance. Thus, we are not bound by the Commission’s characterization of the purpose behind its amendment.
United States v. Mondaine,
We conclude that a defendant is entitled to have the government exercise its discretion under the version of § 5K1.1 in effect at the time the defendant provides the assistance. Section 5K1.1 speaks to the assistance a defendant provides to the government, rather than the criminal conduct for which the defendant was convicted. Thus, the retroactivity analysis turns on which version of § 5K1.1 was in effect when she participated in the numerous briefings with federal agents — not when she committed the unlawful conduct to which she pled guilty.
Cf. Miller,
Unfortunately, the record is silent on precisely when Gerber attempted to assist the government. What evidence does exist, however, suggests that Gerber did not provide assistance to the government until after the November 1989 amendment to § 5K1.1 took effect. The unlawful conduct to which she pled guilty occurred in March and April 1989, but the government did not obtain an indictment until July 10, 1992. Moreover, Gerber reveals that, as part of the guilty plea entered on October 8, 1992, she agreed to cooperate with the federal agents in exchange for the government’s consideration of a § 5K1.1 motion for substantial assistance. In any event, because the record does not plainly show that Gerber provided assistance to the government before the November 1989 amendment to § 5K1.1, and because she did not previously raise as error the application of the November 1989 amendment to § 5K1.1, we cannot find plain error. 5
IV.
Accordingly, we AFFIRM Gerber’s sentence.
Notes
. After examining the briefs and appellate record, this panel has determined unanimously that oral argument would not materially assist the determination of this appeal. See Fed.R.App.P. 34(a); 10th Cir.R. 34.1.9. Therefore, the case is ordered submitted without oral argument.
. “No Bill of Attainder or ex post facto Law shall be passed.” U.S. Const, art. I, § 9, cl. 3.
. There is no dispute in this case that the district court lacks the authority to grant a downward departure under § 5K1.1 absent a motion for such a departure from the government.
. We recognized in
Saucedo
that the Ex Post Facto Clause places a “limitation on the powers of the Legislature.”
Saucedo,
. Because we conclude that Gerber has not satisfied the first prong of
Miller,
we need not reach the second prong, namely, whether the November 1989 amendment to § 5K1.1 disadvantaged Gerber by replacing the good-faith standard with the requirement that the defendant actually provide substantial assistance.
Miller,
