Final answer:
Alcohol consumption decreased during Prohibition due to laws like the Eighteenth Amendment and Volstead Act, but widespread demand persisted leading to illegal trade and enforcement challenges.
Step-by-step explanation:
During national alcohol prohibition from 1920 to 1933, alcohol consumption decreased. Prohibition came about through the efforts of temperance movements and Progressive reformers, which led to the enactment of the Eighteenth Amendment and the Volstead Act. Despite these laws, there was persistent and widespread demand for alcohol, leading to significant illegal trade and eventually to the amendment's repeal. Illegal operations by organized crime figures like Al Capone flourished, and enforcement proved challenging due to public opposition and a lack of adequate resources. While there was a reduction in average alcohol consumption, particularly among working-class Americans, the period of Prohibition also saw a decline in the public's respect for law enforcement and an increase in organized crime.