States can remove their right to vote, just like for felons.
Really?
Yes, as far as I can tell. In fact some states had such "pauper laws" as late as the 1930s. I'm aware of no court case striking them down. (The states themselves eliminated them by legislation.)
There's a poster on FR who's a real expert on this. He posted to a lot of links about it to me either last fall or earlier this year. Unfortunately I don't recall his screenname. I posted about this before I heard from him, but my research using google didn't turn up anything like what he had.