A sentence for unlawful reentry following removal from the United States is affirmed over claims that: 1) the district court plainly erred by enhancing his sentence based on the determination that his prior Texas conviction for unlawful delivery of cocaine qualified as a drug-trafficking offense under the sentencing guidelines; and 2) the felony and aggravated felony provisions of 8 U.S.C. section 1326(b) are unconstitutional.