The Prohibition of alcohol, usually referred to as just 'Prohibition,' was the banning of alcohol in the United States between 1920 and 1933. The 'Dry movement was led by rural Protestants, and was presented at the time as a public victory for morals and health, but once the laws were passed people did little to reinforce them.
However, the consumption of alcohol overall went down by half in the 1920s and it remained below pre-Prohibition levels until the 1940s, despite the 'Speakeasies' run by Bootleggers, which were effectively underground pubs run illegally that made a lot of money.