William Greene appeals the eighty-seven month sentence imposed following his guilty plea to possessing with intent to distribute more than fifty grams of cocaine base. Greene argues the district court improperly applied a presumption of reasonableness to the applicable guidelines range. We vacate Greene’s sentence and remand for resentencing.
I
On May 17, 2006, Greene was indicted for possession -with intent to distribute more than fifty grams of cocaine base in violation of 21 U.S.C. §§ 841(a)(1), (b)(1)(A). Pursuant to a plea agreement, *906 Greene entered a plea of guilty on the single count of the indictment. An initial presentence investigation report (“PSR”) concluded Greene’s advisory guideline range was 108 to 135 months, based on an adjusted offense level of 31 and a criminal history category of I. The report noted, however, that Mr. Greene faced a ten year statutory minimum sentence that overrode the low-end of this range.
Following concerns over the adequacy of Greene’s counsel, the court appointed the Federal Defender Office to represent Greene. Shortly thereafter, Greene submitted to a proffer interview with the government and became eligible for a safety valve reduction. This adjustment eliminated the ten year statutory minimum and reduced Greene’s advisory range to 87 to 108 months.
At sentencing, Greene requested a sentence below the applicable guidelines range based on the factors set out in 18 U.S.C. § 3553(a). Specifically, Greene requested a more lenient sentence based on (1) the Sentencing Commission’s conclusions regarding the disparity between the penalties for cocaine powder and cocaine base, (2) his age, (3) his medical condition, (4) his prior counsel’s deficient representation, and (5) his work record. At the time of sentencing, Greene was sixty years old and was suffering from several health-related problems, including diabetes and hypertension. In addition, Mr. Greene was recovering from a heart attack he suffered in 2004.
The district court noted under current Eighth Circuit law it had very limited discretion in varying from the advisory guideline range. With respect to the circumstances in this particular case, the court concluded Eighth Circuit precedent precluded it from imposing a downward variance from the low-end of the advisory range. The court made clear, however, if it had the opportunity it would have imposed a lower sentence based on
United States v. Booker,
II
Before reaching the merits of Greene’s appeal, we must address the government’s motion to dismiss. After oral argument the government filed a motion to dismiss Greene’s appeal based on a waiver provision in Greene’s plea agreement. We hold the government waived this argument and, therefore, deny the government’s motion.
This Court routinely enforces the doctrine of waiver and declines to address arguments a party fails to raise in its opening brief.
See, e.g., Hailemichael v. Gonzales,
Here, the government did not raise the waiver argument at sentencing in response to Greene’s request for a sentence outside the applicable guidelines range. Nor did it raise the argument in its appellate brief. Indeed, the government’s brief expressly stated there was no plea agreement. It was not until oral argument that the government, for the first time, suggested Greene’s plea agreement foreclosed him from seeking a sentence outside the applicable guidelines range. Because the rec
*907
ord makes clear the government waived this argument, we decline to address it here.
See Latorre v. United States,
Ill
This court reviews a district court’s sentence determination under an abuse-of-discretion standard. The United States Supreme Court recently clarified the scope of our review:
[T]he appellate court ... must first ensure that the district court committed no significant procedural error, such as failing to calculate (or improperly calculating) the Guidelines range, treating the Guidelines as mandatory, failing to consider the § 3553(a) factors, selecting a sentence based on clearly erroneous facts, or failing to adequately explain the chosen sentence-including an explanation for any deviation from the Guidelines range. Assuming that the district court’s sentencing decision is procedurally sound, the appellate court should then consider the substantive reasonableness of the sentence imposed under an abuse-of-discretion standard.
Gall,
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According to Greene, the record demonstrates the district court interpreted this court’s binding precedent to require application of a presumption of reasonableness to the applicable guidelines range and to preclude a variance in the absence of extraordinary circumstances. As the Supreme Court made clear in
Rita v. United States,
— U.S. —,
The record in this case makes clear the district court applied a presumption of reasonableness to the applicable guidelines range. At sentencing, the district court stated, “I do not believe based on current Eighth Circuit law that I am permitted to do a variance in this case. However, if I had an opportunity to do a variance based on Booker, I would have done so.” Sent. Tr. at 17. The district court also said it would await the Supreme Court’s decision in Rita “to figure out whether I have some discretion or whether really I’m pretty much bound by the federal sentencing guidelines unless there’s something that they haven’t taken into account.” Id. at 19.
In light of
Rita,
the district court’s application of a presumption of a reasonableness was a significant procedural error.
See Gall,
Further, we do not believe this error was harmless.
1
The government bears the burden of proving the district court’s error was harmless and must show that no “grave doubt” exists as to whether the error substantially influenced the outcome of the proceedings.
United States v. Cullen,
IV
Accordingly, we vacate Greene’s sentence and remand for resentencing consistent with this opinion. 2
Notes
. We find, and the government does not disagree, Greene raised a timely objection during sentencing and, therefore, preserved his challenge.
. We note at resentencing, the district court "may consider the disparity between the Guidelines’ treatment of crack and powder cocaine offenses” in making a determination whether "a within-Guidelines sentence is 'greater than necessary' to serve the objectives of sentencing.”
Kimbrough v. United
States, - U.S. -,
