The thing is unless the dingbat governor had authorized somewhere to go Nagin had no authority outside the city limits of New Orleans. He had to have somewhere to put those nearly 500,000 people. SHE froze, his hands were tied. The shelters that could be used would have had to be north of interstate 10 because there are NONE south of the interstate in the state that could be used in a CAT 5 storm.
At the time the decision had to be made the whole state was still in the cone of probability. It's a logistics nightmare and it should have been handled better. Time was not on their side at all.
Nagin shouldn't have said most of what he said but hey we weren't the one's with all those people's lives in our hands either knowing that the possibility that many could have died. All of the scenarios before have said that the death count could be that high.
Bottom line, most of the blame is on Kathleen Blanko's shoulders. She failed and failed miserably. She did handle things much better with Hurricane Rita but of course none of that is reported in the media.