When they lose the civil war they lose the right to vote. It's not who decides. It will be decided for them by the winners of the war like always. They might even lose the right to own property if they aren't careful. How long these rights are lost may depend on background checks done to find out how much of a villain they were/are.
All the Rats have to do is change the rules when they get into power. Example: Wolf became Governor of my state Pennsylvania after negative attack ads starting a year before election, has PA Supreme Court order redistricting in state so Trump can never win again in PA, broke apart my red suburban district in South Hills of Pittsburgh and lumped it in with Democratic Pittsburgh, we are shellshocked, mission accomplished, local libraries and churches have seminars on why redistricting is fair and just for you. Shut up, comrade.