Which amendment lowered the voting age to 18?

The amendment that lowered the voting age to 18 is the 26th Amendment. Ratified in 1971, this amendment was significant in expanding democratic participation, particularly in response to arguments that if individuals were old enough to be conscripted into military service, they should also have the right to vote. The movement led to a greater recognition of the rights of younger citizens, and the passage of this amendment was both a reflection of and a catalyst for social change during that period in U.S. history.

In contrast, the other amendments mentioned address different aspects of voting rights and eligibility. The 22nd Amendment limits the number of terms a president can serve, the 19th Amendment grants women the right to vote, and the 15th Amendment prohibits the denial of the right to vote based on race, color, or previous condition of servitude. None of these amendments directly address the voting age.