Which amendment established the legal voting age in the United States?

The Twenty-sixth Amendment is the correct answer because it specifically addresses the legal voting age in the United States, lowering it from 21 to 18 years old. Ratified in 1971, this amendment was influenced by the significant youth involvement in the Vietnam War, which sparked a nationwide debate over the fairness of young adults being eligible for military service but not being allowed to vote.

In contrast, the First Amendment deals with fundamental rights such as freedom of speech and religion, while the Eighteenth Amendment established the prohibition of alcohol, and the Twenty-fourth Amendment eliminated poll taxes in federal elections. None of these amendments pertain to the voting age directly, thus highlighting the significance of the Twenty-sixth Amendment in establishing and solidifying the right to vote for younger citizens.