Regardless of whether it was a disaster area, an emergency disaster area, or an incident of national significance, help arrived early and in force. The implication of the article at the top of this thread, that the people languished for days for want of Chertoff's memorandum declaring an Incident of National Significance, is ludicrous.
The implication of the article, as you take it (not that you agree with the article - just saying that you take the article as saying this), is that FEMA had full command and control as of August 31. Even if it was entitled to it, FEMA didn't have it. And even if it had it, it has to rely of field reports provided by state or media actors in order to command and control effective relief.
And of course, none of what went down hinged on Chertoff's declaration of Incident of National Significance. The Coast Guard and others were out there working without FEMA orders.