The problem I have is with your right to vote being REVOKED like so many states do. I have no problem, personally or under the constitution, with your right to vote being suspended while you are serving your sentence but it should be restored automatically once that sentence is done. It shouldn't be used as a matter of continuing punishment-rather the restoration of the right to vote should be a signal to the person that they can now be a productive part of society.
The problem is many (mostly southern) states revoke the right to vote-either permanently or you have to go before a commission and plead to restore your right to vote. That was the law in Florida for years, although it my understanding that they may have revised it recently. My state suspends the right to vote like I set forth in the first paragraph.
Here's an interesting article on the subject:
http://www.ncsl.org/research/elections-and-campaigns/felon-voting-rights.aspx
BTW I'm what OP would call a leftist. Unlike the GOP we don't feel compelled to march in lockstep.