Josh Marshall at Talking Points Memo has posted a timeline of Katrina-related events.
It is WELL worth a look. Pay special attention to these facts (yes, they are FACTS, George):
Saturday, August 27: President Bush officially declares that a "state of emergency" exists in Louisiana and ordered Federal aid to the affected areas to complement state and local relief efforts.
Monday, August 29: FEMA director Michael Brown waits 5 hrs after Katrina has hit to ask his boss, Michael Chertoff, for 1000 Homeland Security employees to be sent to the region and gave them two days to arrive. Brown urges emergency service personnel "not to respond to hurricane impact areas unless dispatched by state, local authorities."
Tuesday, August 30: President Bush delivers a speech on the 60th anniversary of V-J Day in which he talks mainly of the need to "stay the course" in Iraq.
There's lots more, of course, but just those facts alone display an unbreakable chain of negligence that is criminal and must be prosecuted. Period.