My theoretical theory on that is we assume a person is law abiding and non-violent until he proves otherwise. Then we take away his rights.
But of course, that would be harking back to the days of old before all the pre-emptive right-taking came about in modern politics.
Terry, 230RN
So how about this - driver's licenses (or state ID cards) are cross referenced with criminal records, with a big CVF ("Convicted Violent Felon") on the driver's licenses of convicted violent felons. Everyone without a "CVF" can buy anything they want, where ever and when ever they want? (The alternative is to keep the proven bad guys in jail and just not let them run around loose.)
I'd also include criteria for disqualifying people who are mentally ill, but seeing as I put the pill pushing quacks of modern psychiatry (who'd no doubt be making that determination) on a par with astrologers and phrenologists, I wouldn't have much confidence in the results.