Iam reading my u. s. history textbook, and i thought: if in1919 they passed the eighteenth amendment to ban the manufacture, sale, or transport of alcoholic beverages, why did the congress had to pass the volstead act later in the same year to enact the eighteenth amendment? if an amendment is something that we could not violate or could not change, why did the congress had to pass the volstead act?

I got the answer from a website that I really trust so I hope it helps

Congress passes the Volstead Act over President Woodrow Wilson’s veto. The Volstead Act provided for the enforcement of the 18th Amendment to the U.S. Constitution, also known as the Prohibition Amendment.

The movement for the prohibition of alcohol began in the early 19th century, when Americans concerned about the adverse effects of drinking began forming temperance societies. By the late 19th century, these groups had become a powerful political force, campaigning on the state level and calling for national liquor abstinence. In December 1917, the 18th Amendment, prohibiting the “manufacture, sale, or transportation of intoxicating liquors for beverage purposes,” was passed by Congress and sent to the states for ratification. In January 1919, the 18th amendment achieved the necessary two-thirds majority of state ratification, and prohibition became the law of the land.

The Volstead Act, passed nine months later, provided for the enforcement of prohibition, including the creation of a special unit of the Treasury Department. Despite a vigorous effort by law-enforcement agencies, the Volstead Act failed to prevent the large-scale distribution of alcoholic beverages, and organized crime flourished in America. In 1933, the 21st Amendment to the Constitution was passed and ratified, repealing prohibition