Why was prohibition unsuccessful?

Prohibition in the US (1920-1933)

Prohibition in the US was a result of the Temperance Movement, which sought to cure the social evils blamed on the consumption of Alcoholic Beverages. The 18th Amendment ratified in 1919 prohibited the manufacture, trade, and sale of liquor, wine, and spirits beginning in 1920. Its enforcement was under the Volstead Act, or National Prohibition Act.

While many saw a benefit from the lack of open sale, criminal elements ("bootleggers") soon appeared that took advantage of the continued demand for alcohol. Smugglers and illegal distilleries provided the supply, while clandestine illegal bars (speakeasies) proliferated. Practically anyone who actually wanted a drink could find one. Competition among rival gangsters for the lucrative operations resulted in destruction, murders, and widespread public corruption.

Finally, the lawlessness and violence of the gangs convinced the public that Prohibition was a noble but unattainable goal. It was repealed by the 21st Amendment in 1933, which used state conventions to avoid the politics of state legislatures.