I think that bwana's point still stands. The USA was able to mobilise almost immediately to help Israel but took an unacceptable amount of time to help those trapped as a result of Huricane Katrina.
Now there are mitigating circumstances. Helping Israel would merely involve issuing an executive order from the US President. The New Orleans area involves activating an emergency response coordinated by a number of parties (Lousiana governor, New Orleans mayor) but apparently does not call for any effort from the President.
