In the US civil rights are not restore in some states until a period of crime free behavior can be shown.
That's not civil at all. The punishment ends when the sentence ends. Even during a period of parole, all normal societal rights that don't affect considerations of safety should be restored.
If their electorate automatically became that, within which the prison lies, they could indeed,in a tight election, carry the balance of power.
In turn breathing human beings, seams quite obvious, still exist and are a part of this world !
from thier jail cells to vote
Of course not you dummy. You don't get to vote from your home.