The 18th amendment prohibited the transportation, manufacture, and sale of alcohol. This amendment was passed by congress in December 1917 and ratified in January 1919, but didn’t go into effect until January 20th, 1920. After the 18th amendment was ratified, the Volstead act was sent to Congress, its purpose was to help enforce the 18th amendment. Woodrow Wilson vetoed the Volstead act, but Congress over ruled it.
Before the 18th amendment was put into effect many states had their own prohibition laws in affect due to