Either lock them up for life or restore their rights and I mean all of them. You can't be a "half citizen"
Before the flames come pouring in remember, everything from failure to pay child support to murder, is now a felony, its not just violent crimes.
Sure you can. Mentally incompetent people are "half citizens" (your phrase). So are children.
In some cases they will followed by a felony. They may be unable to vote; hold a corporate office; become a CPA or Lawyer; own a gun, etc.