Final answer:
The 18th Amendment was repealed by the 21st Amendment in 1933 due to difficulties in enforcement and increased crime in the illegal alcohol trade during Prohibition.
Step-by-step explanation:
The 18th Amendment was repealed in 1933 by the 21st Amendment. Prohibition, which banned the production, sale, and transportation of alcohol, became difficult and expensive to enforce. The illegal production of alcohol led to a rise in crime, making the amendment unpopular and ultimately repealed.
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