Correct me if I am wrong but I believe it was the Mayor that ordered the weapons confiscation in NO.
New Orleans was at that point legally part of international waters and not the United States; otherwise, the Second Amendment would have applied. I'm still not sure why FEMA ever got involved as those waters then lied beyond their jurisdiction.
Oops, I forgot. The Schedule of Emanations and Penumbras clearly states that its "offense to petty bureaucrats, criminal gangs, and liberals" clause takes precedence over the Second Amendment.
I'm not sure, eastforker, but I believe you are right.
At any rate, I could see state authorities pulling the same thing, like the state's National Guard.
And the BATF and US Marshalls lended him a hand.