Prohibitionists were individuals and groups who advocated for the prohibition of alcohol in the United States, culminating in the 18th Amendment, which took effect in 1920. They believed that banning alcohol would reduce crime, improve public morality, and enhance social welfare. The movement was often associated with religious groups and social reformers, who viewed alcohol as a source of societal problems. However, Prohibition ultimately led to unintended consequences, including the rise of organized crime and a widespread disregard for the law, culminating in its repeal in 1933.