Well, how about 3/5 of a vote? There's precedent, in a way.
There was no such thing as 3/5 of a vote, ever. There was a provision that slave states could only count 3/5 of their inhabitants for purposes of seats in congress. The logic being, you don’t get allocated extra seats for people whom you are holding against their will.
Felons who can’t vote are not another ‘class’ of citizen. They broke a law and lost a right of citizenship as a consequence. Not really that complicated.
Thing is, if I were an illegal what would I be worrying about? Getting my life tossed in the crapper by being deported. Not not being able to vote.
My point is that this checkmates a BIG anti-American, ultra liberal weapon. They use it to keep Mexicans in line. Yet most Hispanics are by nature conservative, Without fear of deportation, they could vote the way they want to.