Final answer:
A state suffrage law that sets a maximum age for voting would violate the 26th Amendment of the federal Constitution, which prohibits age-based disenfranchisement for citizens 18 years and older.
Step-by-step explanation:
A law setting a maximum age for voting would violate the federal Constitution. According to the 26th Amendment, states and the federal government cannot deny the right to vote to U.S. citizens who are 18 years and older on account of age. By setting a maximum age for voting, the state would be disenfranchising a segment of the population based on age, which is unconstitutional.
The history of suffrage in the United States demonstrates a clear trend toward expanding the right to vote. Key amendments, like the 15th, 19th, and 26th Amendments, have removed voting barriers based on race, gender, and age, respectively. The 26th Amendment, in particular, was established during the Vietnam War era, reflecting the sentiment that if young Americans were old enough to be drafted for war, they should also be entitled to vote.
Therefore, any state law attempting to infringe upon the voting rights of individuals within the constitutionally protected age range would be in direct violation of the 26th Amendment, rendering it unconstitutional.