What was the main effect of the 18th Amendment?

The 18th Amendment, ratified in 1919, instituted Prohibition in the United States, making it illegal to manufacture, sell, or distribute alcoholic beverages. This was a significant social experiment aimed at improving public morals and health, reflecting the temperance movement's influence during that era. The goal was to reduce crime, corruption, and social problems attributed to alcohol consumption.

The consequence of this amendment led to a rise in illegal production and distribution of alcohol, known as "bootlegging," and the growth of organized crime as criminal organizations took over the supply of alcohol. This amendment was eventually repealed by the 21st Amendment in 1933 due to its widespread unpopularity and the failure to effectively enforce Prohibition.

The other options pertain to different historical developments not linked to the 18th Amendment. Legalization of marijuana is unrelated and was not a focus of the amendment. The establishment of an income tax came with the 16th Amendment, and women's suffrage was granted through the 19th Amendment. These reflect distinct movements and changes in American policy and rights, separate from the effects of Prohibition.