The Eighteenth Amendment to the United States Constitution, ratified on 16 January 1919 and taking effect one year later, prohibited the manufacture, sale, and transportation of intoxicating liquors within the United States and its territories. It is the only constitutional amendment to have been subsequently repealed, a status achieved by the Twenty-First Amendment in 1933. The amendment did not criminalize the consumption or private possession of alcohol, but it provided the federal constitutional basis for the Volstead Act, the legislation that defined enforcement mechanisms and set the threshold for what constituted an intoxicating beverage.
The amendment emerged from decades of temperance advocacy, rooted in Protestant religious culture, public health concerns, and anxieties about urban immigrant communities and their drinking customs. The Anti-Saloon League and the Women's Christian Temperance Union were among the most influential organizations driving the push for a constitutional remedy rather than relying on state-level laws, which varied widely and were subject to repeal. By the time the amendment passed Congress in December 1917, over half of U.S. states had already enacted some form of prohibition.
The fourteen-year period during which the Eighteenth Amendment was in force, commonly called Prohibition, produced significant and contested consequences. Alcohol consumption did decline, particularly in the early years. At the same time, black markets emerged rapidly, organized crime networks expanded, federal and local law enforcement capacity was strained, and widespread evasion of the law was documented across all economic classes. The degree to which Prohibition succeeded or failed - and on what terms success or failure should be measured - remains a subject of historical and policy debate. See History for a fuller account.
Support for the amendment eroded through the late 1920s and accelerated after the onset of the Great Depression, when arguments about lost tax revenue and employment gained traction alongside longstanding objections on civil liberties grounds. The Twenty-First Amendment was ratified on 5 December 1933, making the Eighteenth Amendment the only amendment ever repealed from the U.S. Constitution. The repeal returned authority over alcohol regulation primarily to the states, producing a patchwork of laws that persists in modified form today.
There is broad historical consensus that Prohibition did not eliminate alcohol use and that it contributed to the growth of organized crime. Historians debate the extent and duration of its public health effects, its role in shaping federal law enforcement, and whether its social costs outweighed its benefits. See Eighteenth Amendment - Historical Consensus for sources and scope.