I saw a brief clip of Nagin on the news earlier and he was saying the communications were terrible and he could not get ahold of the Feds to send buses. Of course we all know Nagin had plenty of buses.
But he couldn't use those buses because they didn't have bathrooms. Nagin said so himself.
And everyone knows that before Karl Rove steered the hurricane into New Orleans and blew up the levees, he hung "Whites Only" signs on every restroom at every gas station and rest stop on every possible evacuation route out of the city, just to make sure the blacks were hopelessly trapped to die.