The 18th Amendment, ratified on January 29, 1919, enacted nationwide prohibition of alcohol in the United States, empowering both federal and state enforcement without clear definitions or penalties. Prohibition led to significant issues, including a rise in organized crime and a black market for alcohol, resulting in public discontent and illegal production. Ultimately, the national prohibition ended with the 21st Amendment on December 5, 1933, with Mississippi being the last state to lift it in 1966.