Final answer:
The Twenty-Sixth Amendment lowered the voting age from 21 to 18 in 1971, allowing younger citizens of the United States to participate in voting for federal, state, and local elections.
Step-by-step explanation:
The Twenty-Sixth Amendment to the United States Constitution significantly altered the legal landscape of voting rights by lowering the voting age from 21 to 18. This landmark change was enacted in response to the widespread sentiment during the Vietnam War era that if 18-year-olds were old enough to be conscripted into military service, they should also have the right to vote.
The passage of the amendment in 1971 ensured that citizens of the United States, who are eighteen years of age or older, have their right to vote protected and cannot be denied on account of age. This effectively empowered a new generation to participate in the democratic process and cast their votes in federal, state, and local elections.