Defendant's conviction for possession with the intent to distribute cocaine is affirmed over a claim that the statute of conviction, 21 U.S.C. section 841, is facially unconstitutional. His sentence is vacated and remanded where: 1) a prior conviction in Colorado for third-degree assault does not qualify as a crime of violence under U.S.S.G. section 4B1.2(a)(1), but 2) a remand was necessary to determine whether a career offender enhancement was sustainable under section 4B1.2(a)(2).