Fernando Benito-Herrera appeals his guilty-plea sentence for conspiracy to commit hostage taking in violation of 18 U.S.C. § 1203(a). He argues that the enhancement of his sentence pursuant to United States Sentencing Guidelines § 2A4.1(b)(3) violates Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), because the enhancement was not charged in the indictment and the facts underlying the enhancement were not found by a jury or admitted by him. We do not address whether Benito-Herrera’s appeal waiver applies to his Blakely argument, because, even if he did not waive the right to raise this argument on appeal, his sentence should be affirmed.

In Blakely, the Supreme Court held that the Sixth Amendment prohibits state sentences greater than “the maximum sentence a judge may impose solely on the basis of the facts reflected in the jury *982 verdict or admitted by the defendant.” Blakely, 124 S.Ct. at 2537. In United States v. Booker, — U.S.-, 125 S.Ct. 738, 749-50, 160 L.Ed.2d 621 (2005), the Supreme Court held that the system of enhancements established by the federal sentencing guidelines violated the Sixth Amendment as construed in Blakely.

This court’s review is for plain error because Benito-Herrera’s Blakely argument is raised for the first time on appeal. See United States v. Mares, 402 F.3d 511, 520 (5th Cir. 2005), petition for cert, filed (U.S. March 31, 2005) (No. 04-9517). The enhancement of Benito-Herrera’s sentence under U.S.S.G. § 2A4.1(b)(3) was plain error because the facts underlying the enhancement were found by the sentencing judge under a mandatory guidelines system. See Mares, 402 F.3d at 520-21. Nothing in the record indicates, however, that the plain error affected Benito-Herrera’s substantial rights. See id. at 522. Accordingly, Benito-Herrera’s sentence is AFFIRMED.