Herbert Hoover called prohibition a "noble experiment," but the effort to regulate people's behavior soon ran into trouble. Enforcement of prohibition became very difficult. Soon, such terms as "bootlegger," "bath tub gin," and "speakeasy" became household words. Gangs of hoodlums became more powerful as they trafficked in alcohol. By the 1930s, a majority of Americans had tired of the noble experiment, and the 18th Amendment was repealed.