The bill was vetoed by President Woodrow Wilson (largely on technical grounds, because it also covered wartime prohibition) but overridden by Congress on the same day, October 28, 1919. The Act specified that "no person shall manufacture, sell, barter, transport, import, export, deliver, furnish or possess any intoxicating liquor except as authorized by this act". It did not specifically prohibit the purchase or use of intoxicating liquors. The act defined intoxicating liquor as any beverage containing over 0.5% alcohol and superseded all existing prohibition laws in effect in states with such legislation. The combination of the Eighteenth Amendment to the United States Constitution and the laws passed under its authority became known simply as "Prohibition" and enormously affected United States society in the 1920s (popularly known as the Roaring Twenties).
The effects of Prohibition were largely unanticipated. Production, importation and distribution of alcoholic beverages—once the province of legitimate business—were taken over by criminal gangs, which fought each other for market control in violent confrontations, including mass murder. Top gangsters became rich and were admired locally, such as Omaha's Tom Dennison, and nationally, such as Chicago's Al Capone. This effectively made murderers into national celebrities. Enforcement was difficult because the gangs became so rich that they were often able to bribe underpaid and understaffed law-enforcement personnel and hire top lawyers. Many citizens were sympathetic to bootleggers and respectable citizens were lured to the romance of illegal speakeasies, also called "blind pigs". The loosening of social mores during the 1920s included popularizing the cocktail and the cocktail party among higher socio-economic groups. Those inclined to assist authorities were often intimidated, even murdered. In several major cities—notably those which served as major points of liquor importation, including Chicago and Detroit—gangs wielded effective political power. A Michigan State Police raid on Detroit's Deutsches Haus once netted the mayor, the sheriff, and the local congressman.
Section 29 of the Act allowed 200 gallons (the equivalent of about 1000 75 cl bottles) of "non-intoxicating cider and fruit juice" to be made each year at home. Initially "intoxicating" was defined as anything over 0.5%, but the Bureau of Internal Revenue soon struck that down and this effectively legalised home wine-making. Some vineyards embraced the sale of grapes for making wine at home; Zinfandel grapes were popular among home winemakers living near the vineyards, but its tight bunches left their thin skins vulnerable to rot, due to rubbing and abrasion, on the long journey to East Coast markets. The thick skins of Alicante Bouschet were less susceptible to rot, so this and similar varieties were widely planted for the home wine-making market.
Prohibition lost advocates as alcohol gained increasing social acceptance and as the effects of prohibition on disrespect for law and the growth of organized crime became apparent. By 1933, public opposition to prohibition had become overwhelming. In January of that year, Congress sought to pre-empt opposition with the Cullen-Harrison Act, which legalized "3.2 beer" (i.e., beer 3.2% alcohol by weight or 4% by volume), rather than the 0.5% limit defined by the original Volstead Act, but the Cullen-Harrison Act was insufficient. Congress proposed an amendment to repeal Prohibition (the Blaine Act) in February and, on December 5, 1933, the nation ratified the Twenty-first Amendment, which repealed the Eighteenth Amendment, made the Volstead Act unconstitutional, and restored control of alcohol to the states, up until the creation of the Federal Alcohol Administration in 1935.