Louis Gerald Indell appeals his sentence imposed after pleading guilty to possession of a firearm and ammunition by a convicted felon, in violation of 18 U.S.C. § 922(g)(1), asserting the district court erred under United States v. Booker, — U.S. -, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005). We vacate and remand for resentencing.

I. DISCUSSION

Because Indell raised a constitutional objection to his sentence based on Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), before the district court, we review his sentence de novo, but will reverse only for harmful error. See United States v. Paz, 405 F.3d 946, 948 (11th Cir. 2005). We have clarified there are two types of Booker error: (1) Sixth Amendment, or constitutional, error based upon sentencing enhancements, imposed under a mandatory Guidelines system, neither admitted by the defendant nor submitted to a jury and proven beyond a reasonable doubt; and (2) statutory error based upon sentencing under a mandatory Guidelines system. United States v. Shelton, 400 F.3d 1325, 1329-30 (11th Cir. 2005).

A. Constitutional Error

1. Constitutional Error

A district court does not commit Booker constitutional error by relying on past convictions to enhance a defendant’s sentence. Shelton, 400 F.3d at 1329. Because Indell’s sentence was enhanced based on past convictions, there is no constitutional error. 1

B. Statutory Error

Although the district court committed no constitutional error in sentencing Indell, because the district court sentenced him under a mandatory Guidelines scheme, there was Booker statutory error. See Shelton, 400 F.3d at 1330-31. “A non-constitutional error is harmless if, viewing the proceedings in their entirety, a court determines that the error did not affect the sentence, or had but very slight effect. If one can say with fair assurance ... that the sentence was not substantially swayed by the error, the sentence is due to be affirmed even though there was error.” United States v. Mathenia, 409 F.3d 1289 (11th Cir. 2005) (internal quotation marks and brackets omitted). The Government has the burden of showing the error was harmless. Id.

In United States v. Davis, 407 F.3d 1269, 1271 (11th Cir. 2005), using the higher harmless beyond a reasonable doubt standard used in Booker constitutional error cases, we held the district court’s grant of the government’s U.S.S.G. § 5K1.1 motion for a downward departure based on the defendant’s substantial assistance neither removed nor rendered harmless beyond a reasonable doubt any Booker error. In so holding, we reasoned the § 5K1.1 *362 motion did not give the sentencing court “unfettered” discretion, as argued by the government, but rather gave the court only limited discretion to consider the defendant’s assistance. Id. Noting the sentencing court could not permissibly consider the sentencing factors announced in 18 U.S.C. § 3553(a) when exercising its discretion, we concluded it was unclear what the sentencing court would have done had it understood the Guidelines to be advisory and had properly considered the § 3553(a) factors. Id.

The Government asserts the error is harmless because Indell made two requests for downward departures that provided the district court with discretion to give Indell a sentence lower than the bottom of the Guidelines range, and the district court declined to depart downward. We conclude the error was not harmless. In reviewing the record, it is unclear what the sentencing court would have done had it understood the Guidelines to be advisory. Although the sentencing court commented that Indell’s criminal history reflected a need to protect the public and that Indell would be “better off’ incarcerated in light of his drinking problem, thus considering the need to protect the public and provide the defendant with needed medical care, see 18 U.S.C. § 3553(a)(2)(C), (D), we cannot say what the sentencing court would have done had it understood the Guidelines to be advisory. The Government cannot show the sentence was not substantially swayed by the error. See United States v. Mathenia, 409 F.3d 1289 (11th Cir. 2005).

II. CONCLUSION

The district court erred in treating the Guidelines as mandatory, and that error was not harmless. Thus, we vacate and remand for resentencing in light of Booker. We note the district court correctly calculated Indell’s Guidelines range of 30 to 37 months’ imprisonment. See United States v. Crawford, 407 F.3d 1174, 1178-79 (11th Cir. 2005) (stating after Booker, district courts must consult the Guidelines and “[t]his consultation requirement, at a minimum, obliges the district court to calculate correctly the sentencing range prescribed by the Guidelines”). Thus, on remand, the district court is required to sentence Indell according to Booker, considering the Guidelines advisory range of 30 to 37 months’ imprisonment and “other statutory concerns as well, see [18 U.S.C.] § 3553(a) (Supp. 2004).” Booker, 125 S.Ct. at 757. 2

VACATED AND REMANDED.