Rivera

Mario Antonio Rivera, an alien, has been convicted of at least ten offenses and has been removed from the United States ten times, most recently on December 5, 2008. Less than six months after he was last removed, he was again arrested as he attempted to cross the border from Mexico into the United States. On January 29, 2010, Rivera pleaded guilty to a violation of 8 U.S.C. § 1326 — for unlawfully attempting to reenter the United States after having previously been removed — and was sentenced to a 37-month term of imprisonment, the low end of the range prescribed by the Sentencing Guidelines.

In calculating the prescribed range, the district court increased the offense level by eight levels because Rivera “previously was deported, or unlawfully remained in the United States, after ... a conviction for an aggravated felony.” U.S.S.G. § 2L1.2(b)(l)(C) (emphasis added). The term “aggravated felony” is defined to include a theft offense “for which the term of imprisonment [is] at least one year.” 8 U.S.C. § 1101 (a)(43)(G). The district court determined that any one of Rivera’s three prior felony petty theft convictions under Cal.Penal Code §§ 484(a) and 666 would be…