One hypothesis that I’m examining is that the 26th Amendment adopted the constitutional views expressed by Voting Rights Act cases from the 1960s.
The background law on suffrage in 1971 (when the 26th was ratified) was the Voting Rights Act and broad enforcement cases like Katzenbach. Indeed, the original (narrower) provision to lower the voting age to 18 came in the VRA amendments enacted in 1970. The Court upheld most of that statute in Oregon v. Mitchell but rejected its lowering of the voting age for state elections. Congress then swiftly rejected that interpretation with the 26th Amendment.
There was some commentary at that time that the 26th Amendment should be read as combatting the same evils as the 15th Amendment did–as understood by the Voting Rights Act. (Enough commentary? I’m not sure.) This line of thought was that college students were being denied the right to vote through the same devices that were used to stop Blacks from voting in the South.
If my hypothesis is correct, then the broad version of the Voting Rights Act now repudiated by the Court survives in one area only–age discrimination.
Stay tuned.