I'm not sure which Katrina thread this should go in, so I'll put it here. I hate to defend public officials of any sort, but I must offer this defense of state/local officials against the attack that they should have forced evacuation of New Orleans prior to the storm. Two facts need to be taken into consideration:
1. Gulf hurricanes tend to take a sharp turn to the east prior to landfall. Katrina, in fact, did this. Had it not been as unusually large as it was, New Orleans would have been largely spared major damage.
2. A forced evacuation is very expensive, and an unnecessary forced evacuation would have been politically suicidal.
A parish (county) official earlier this year called for a voluntary evacuation of his parish for a hurricane that ended up missing the area. He was crucified in the local media for this "lapse in judgement" and the Governor herself publicly reprimanded him for the action.
Local officials were very stern and consistent in their warnings to get out. A forced evacuation would have been nearly impossible to execute, extremely expensive and potentially deadly had it proved unnecessary. In hindsight, they should have tried it, but I can understand why they made the decisions that they did. Several improvements had been made to previous evacuation plans, and by and large, the evacuation worked quite well, especially given the relatively short warning period.