Subject: Re: The 2A is obsolete
So, for example, Texas could pass a law that mandated every citizen 18 or older be issues 5 AR-15s and 10000 rounds of ammo, because Texas feels that's what's needed to support a state militia?

Oh, they could do that now. States have enormous legislative power. If Texas wanted to hand out 5 AR-15's and ammo to every adult, there's nothing stopping them. And just because a neighboring state might prefer they didn't wouldn't be any legal obstacle to them doing so, if they chose.