How old must citizens be to vote for President?

Citizens must be at least eighteen years old to vote in presidential elections. This age requirement is established by the 26th Amendment to the United States Constitution, ratified in 1971, which guarantees that citizens who are eighteen years of age or older cannot be denied the right to vote based on age. The shift to eighteen as the minimum voting age was largely influenced by arguments that if individuals were old enough to be drafted for military service during the Vietnam War, they should also be allowed to participate in the democratic process through voting. Therefore, the correct answer highlights the legal standard that enables young adults to engage in governance and exercise their rights as citizens.