Watson v. United States, 552 U.S. 74 (2007), is a case decided by the Supreme Court of the United States. The Court had earlier held in Smith v. United States (1993) that the exchange of a gun for drugs constituted "use" of a firearm for purposes of a federal statute imposing penalties for "use" of a firearm "during and in relation to" a drug trafficking crime; in Watson, the court decided that a transaction in the opposite direction does not violate the same statute.