A former mayor was convicted under 18 U.S.C. § 666 for accepting money from a contractor after the city awarded contracts. The Supreme Court held that § 666 prohibits bribes—payments agreed upon or promised before an official act—but does not criminalize gratuities given afterward as a reward without a prior quid pro quo. The text, statutory history, structure, and federalism concerns distinguished the federal bribery offense from gratuity statutes applicable to federal officials. Because the jury was permitted to convict on an after-the-fact gratuity theory, the judgment was reversed and the case remanded.