On Jan. 16, 1920, what began in the United States as the 18th Amendment?

On January 16, 1920, Prohibition began in the United States under the Eighteenth Amendment.

The Eighteenth Amendment prohibited the manufacture, sale, and transportation of intoxicating liquor nationwide. It was ratified on January 16, 1919, after Nebraska became the 36th state to approve it, but its terms required a one-year delay before taking effect. The Volstead Act supplied the enforcement rules, so national Prohibition formally began at midnight on January 17, 1920.

The amendment grew out of the 19th-century temperance movement, whose supporters argued that alcohol contributed to poverty, domestic violence, illness, and political corruption. The law did not directly ban possession or consumption, creating loopholes that helped fuel bootlegging, illegal distilling, and speakeasies.

Prohibition lasted until December 5, 1933, when the Twenty-first Amendment repealed the Eighteenth. It remains the only U.S. constitutional amendment ever repealed. The date is sometimes described as January 16 because the amendment took effect at the end of that day, while January 17 is the formal start date often used by historians.