Our laws don't make a whole lot of sense on this point. Recidivism rates are high, but not everyone who goes to jail once ends up going back again or becomes a career criminal. Maybe voting rights should be restored automatically, but prosecutors should have the ability to ask that they be suspended indefinitely at sentencing if the person is a career criminal.
tk
BTW: The Republican governor of Florida, Charlie Crist, restored voting rights recently to criminals. Not a popular decision with the base, but he simply felt it was the right thing to do. He's made a number of decisions that haven't played well with some traditional supporters, but he's got a lot of crossover support. I'd like to see him run for president.