Which amendment grants the right to vote to citizens who are 18 years or older?

The amendment that grants the right to vote to citizens who are 18 years or older is the 26th Amendment. Ratified in 1971, this amendment was a significant milestone in expanding voting rights, particularly in response to arguments about the fairness of allowing younger individuals—who could be drafted for military service—to participate in elections. By lowering the voting age to 18, the amendment aimed to ensure that those who bear the responsibilities of citizenship, including military service, also have a voice in shaping the laws and policies that govern them.

The 24th Amendment, on the other hand, prohibits the use of poll taxes in federal elections, while the 25th and 27th Amendments deal with presidential succession and congressional pay, respectively. These amendments do not pertain to the voting age. Thus, the 26th Amendment is specifically recognized for affirming the right to vote for those 18 and older, making it the correct choice for this question.