Hmmm. Interesting. Given the context of the Framer’s Debates, I don’t think I see any legal or Constitutional impediment to States requiring enrollment in some form of militia, but not necessarily as a prerequisite to owning a firearm. “The Knox County Long Rifles.” “The Fairfax County Irregulars.” Or something along those lines.
Which some states tried to do initially, Back When. But dropped it for practical reasons. If you’ve ever seen the National Guard at its worst, you’d understand why. If you’ve ever seen the National Guard at its best (and it did go a very long way to cleaning up its act after Gulf War I), I’d personally have no problem with a one-weekend-a-month obligation, but not as a prerequisite to owning an ordinary hunting rifle or handgun.
But if this shakes out in the SC the way gun-rights advocates would wish (and the way this current case seems to be inclined), it might just undermine this line of thought.
As far as automatic weapons are concerned, if we follow your line of thinking, then yeah, possession of fully-automatic weaponry might become more prevalent, but probably only to those enrolled in the State Militias, with clean records, good attendance, and all that.
The averge Joe would still probably have to go through the ATF’s administrative procedures to acquire a fully-automatic weapon. Which, IMO, is not necessarily a bad thing, so long as Congress repeals the law freezing the registry, in order to bring the prices back down out of the stratosphere. IOW, fully-automatic weapons would be easier to acquire strictly from a price perspective, not a legal one.
Otherwise, gun-control advocates who can gather the votes could still have effective bans on firearms (or certain classes of firearms at a minimum) by the simple expediant of severely restricting membership in the Militia:
“Oh-ho! I see you had a speeding ticket twenty yers ago. Sorry, no Militia membership for you!”
-or-
“Can’t afford an M-16? Sorry, you can’t join the Militia.”
-or-
“Sorry, the Militia is currently at its maximum membership of 50 people. Check back next year.”
If you think that second bit is gun-nut paranoia, check out New York state’s history WRT enrollment in their firearms/hunter safety classes.
Edit: !@#$% coding tags. Preview is my friend, but we don’t talk much.