What age must citizens be to vote in federal elections according to the Constitution?

According to the Constitution of the United States, citizens must be at least eighteen years old to vote in federal elections. This requirement is established by the 26th Amendment, ratified in 1971, which explicitly prohibits the denial of the right to vote to citizens aged eighteen and older based on age. Prior to the 26th Amendment, the minimum voting age was set at twenty-one, which reflects historical practices that have since evolved. The choice of eighteen as the minimum age aligns with the societal view that individuals at this age possess the maturity and responsibility necessary to participate in the democratic process. Voting is a fundamental right, and the amendment was significant in expanding this right to a larger segment of the population, particularly younger citizens who could serve in the military and make other significant decisions.