Patel v. Mukasey, 526 F.3d 800, ___ (5th Cir. Apr. 29, 2008) ("The purpose of the categorical approach is to avoid "the practical difficulties and fairness problems that would arise if courts were permitted to consider the facts behind prior convictions .... [which] would potentially require federal courts to relitigate a defendant's prior conviction in any case where the government alleged that the defendant's actual conduct fit the definition of a predicate offense."), quoting Larin-Ullo v. Gonzales, 462 F.3d 456, 463 (5th Cir.2006), citing Taylor v. United States, 495 U.S. 575, 601, 110 S.Ct. 2143, 109 L.Ed.2d 607 (1990).