Since the 1990s, federal prosecutors have, with increasing frequency, sought the death penalty for federal offenses committed in and also punishable under the laws of non-death penalty states. Critics of this practice have pointed out that federal prosecutors can use the federal death penalty to circumvent a state\u27s abolition of capital punishment. Courts, however, have almost unanimously rejected arguments that state law should be a shield from federal punishment for federal offenses. This article proposes a novel way to challenge the federal death penalty\u27s use in a non-death penalty state—the Supreme Court\u27s reasoning in United States v. Windsor. In Windsor, the Court held that federal interference with a state law right arising...