According to another thread it is Bush's fault. I'm still battling the authors of those posts.
I suspect what will emerge from this eventually is that the Homeland Security Act had a major flaw in leaving authority in the hands of local officials. While it seemed like a reasonable idea at the time, especially in the wake of 9/11, no one imagined that those officals would manipulate relief efforts to shift blame for over/under reaction and thus avoid political fall out.