States have been caught purging voters from federal elections. Sometimes because a citizen has died. Sometimes because a citizen missed the last election. Sometimes because the elderly cannot provide a birth certificate or the birth given name is different then they're married name.
It should be no harder processing Americans into the voter system than it is into the prison system!
States receive federal funding if they participate in automatic voter registration using birth certificates and automatic D-registration using death certificates. If states do not meet minimum standards, the federal ballot will be issued for citizens to vote with. State politicians will be voted on a separate state issued ballot.