Gerardo Napoleon Martinez-Casares appeals his guilty-plea conviction and sentence for illegal reentry following deportation, in violation of 8 U.S.C. § 1326. He presents two claims.

First, he contends the district court reversibly erred when it sentenced him pursuant to the mandatory Sentencing Guidelines held unconstitutional in United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005) (Fanfan claim). In this regard, Martinez-Casares’ being sentenced pursuant to a mandatory system constituted error. See United States v. Valenzuela-Quevedo, 407 F.3d 728, 733 (5th Cir.), cert. denied, — U.S.-, 126 S.Ct. 267, 163 L.Ed.2d 240 (2005). Because he preserved his Fanfan claim in district court by objecting based on Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), we review for harmless error. United States v. Rodriguez-Mesa, 443 F.3d 397, 403-05 (5th Cir. 2006). The Government bears the burden of proving beyond a reasonable doubt the district court would not have sentenced Martinez-Casares differently under an advisory system. See United States v. Walters, 418 F.3d 461, 464 (5th Cir. 2005).

The sentencing transcript gives no indication whether the court would have imposed the same sentence had the Guidelines been advisory. Further, contrary to the Government’s claim, that the sentence may be reasonable does not demonstrate the district court would have imposed the same sentence had it not been bound by the Guidelines. See id. at 464-65. Moreover, the court’s granting a downward de *508 parture alone does not prove beyond a reasonable doubt the error did not affect Martinez-Casares’ sentence. See United States v. Garza, 429 F.3d 165, 171 (5th Cir. 2005), cert. denied, — U.S.-, 126 S.Ct. 1444, 164 L.Ed.2d 143 (2006). Therefore, we vacate Martinez-Casares’ sentence and remand for resentencing.

Martinez-Casares also challenges the constitutionality of § 1326(b)’s treatment of prior felony and aggravated felony convictions as sentencing factors rather than elements of the offense that must be found by a jury in the light of Apprendi v. New Jersey, 530 U.S. 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000). This challenge is foreclosed by Almendarez-Torres v. United States, 523 U.S. 224, 235, 118 S.Ct. 1219, 140 L.Ed.2d 350 (1998). Although Martinez-Casares contends AlmendarezTorres was incorrectly decided and that a majority of the Supreme Court would overrule it in the light of Apprendi, we have repeatedly rejected such claims on the basis that Almendarez-Torres remains binding. See United States v. Garza-Lopez, 410 F.3d 268, 276 (5th Cir.), cert. denied, — U.S.-, 126 S.Ct. 298, 163 L.Ed.2d 260 (2005). Martinez-Casares concedes this claim is foreclosed by Almendarez-Torres and circuit precedent; he raises it only to preserve it for further review.

CONVICTION AFFIRMED; SENTENCE VACATED; REMANDED FOR RESENTENCING.