According to the Constitution, what is a requirement to vote?

The Constitution sets a fundamental prerequisite for voting, which is being a citizen who is at least eighteen years old. This age requirement is established by the 26th Amendment to the Constitution, ratified in 1971, which explicitly lowers the voting age from twenty-one to eighteen, ensuring that young adults have the right to participate in elections as soon as they reach the age of legal adulthood.

Being a citizen is also vital because it ensures that voters have a recognized legal status and an allegiance to the country, which is crucial for a functioning democracy. Other options, while they may reflect common practices in some states or societal expectations, are not constitutionally mandated for voting eligibility, as eligibility does not depend on residency status at a state level, age constraints above eighteen, or employment and tax contributions. Therefore, the requirement to be a citizen aged eighteen or older stands as the clear constitutional guideline for voting eligibility.