On June 23, 2016, the Supreme Court decided Mathis v. United States. The Armed Career Criminal Act (ACCA) imposes a 15-year mandatory minimum sentence on a defendant convicted of being a felon in possession of a firearm who also has three prior state or federal convictions “for a violent felony,” including “burglary, arson, or extortion.” To determine whether a prior conviction is for one of those listed crimes, courts apply a “categorical approach”—they ask whether the elements of the offense forming the basis for the conviction sufficiently match the elements of the generic (or commonly understood) version of the enumerated crime. -- Here, petitioner Richard Mathis pleaded guilty to being a felon in possession of a firearm. Because he had five prior Iowa burglary convictions, the Government argued for the 15-year minimum. Generic burglary requires unlawful entry into a “building or other structure.” The Iowa statute under which Mathis was convicted, however, also extended to “any... land, water, or air vehicle.” The District Court determined based on the case record that Mathis had burgled structures and imposed the 15-year ACCA minimum. The U.S Court of Appeals for the Eighth Circuit affirmed. -- By a vote of 5-3, the Supreme Court reversed the judgment of the Eighth Circuit. Justice Kagan delivered the opinion of the Court, which held that because the elements of Iowa’s burglary law – which applies to “any building, structure, [or] land, water, or air vehicle” – were broader than those of generic burglary, Mathis’ prior convictions under the Iowa burglary law could not give rise to an ACCA sentence. Justice Kagan’s majority opinion was joined by the Chief Justice and Justices Kennedy, Thomas, and Sotomayor. Justice Kennedy also filed a concurring opinion. Justice Thomas filed a concurring opinion. Justice Breyer filed a dissenting opinion, in which Justice Ginsburg joined. Justice Alito also filed a dissenting opinion. -- To discuss the case, we have Richard E. Myers II, who is Henry Brandis Distinguished Professor of Law at University of North Carolina School of Law.