This is the work of Dick Cheney, not Obama. But gun confiscation might be in order if martial law were declared, yes. The trick is, it's the neo-cons that set us up for it. Can we get past this year without the white house cancelling elections and staging a very special October surprise? I sure hope so.
RKBA was enshrined in the constitution as a safeguard against exactly this kind of thing. However, let's be realistic; if this were to actually happen, it would succeed, because civilian firepower is no match for the firepower that the U.S. military has at its disposal. On the other hand, if 9/11 did not result in martial law being enacted, I can't imagine what would.