I respect your opinion and understand your view point but i would just like to add something to the debate. It's a fact that a movement/stand can gain momentum and support when states stand up for the will(rights) of its people which can and will influence the debate. I believe if more states took a stand to the federal governments over reach of power then the people in Washington would be changed for the better.
This reason alone is while I would support what what you regard as "meaningless". Legally you may be right but that is something that I believe will have to play out in the courts.
If states have the "right" to ban pretty much any semi-automatic gun then why would they not have the right to pass laws that would refute such a ban. I don't claim to be a legal expert by any means but to me it's something that should be pursued along with many other efforts
I just don't think it's right to dismiss a states ability(not matter what the issue is) to at least try to have some sort of sovereignty with in these United States.