This document summarizes the 18th and 21st Amendments to the US Constitution regarding alcohol prohibition and regulation. It discusses how the 18th Amendment established national prohibition in 1919 due to moral and social concerns, but was repealed by the 21st Amendment in 1933 after prohibition failed to curb drinking and organized crime increased. Since then, states have regulated alcohol sales and consumption within their borders, though the federal government has increasingly intervened through legislation and Supreme Court rulings that have eroded state control afforded by the 21st Amendment.