Glenn Bus(ts) WaPo

"Fully evacuate?'' Yes. As Brendan Loy noted, even 48 hours is really too late -- though Nagin waited much later than that. (I've seen people doing math to the effect that you could have gotten everyone out in 24 hours, but I doubt that New Orleans could have mustered the necessary degree of organization for that.) But certainly a lot of people could have been evacuated who weren't, and that would have improved conditions for the rest, and reduced the burden on relief services. And if Nagin had gotten the buses out, they would have been available for further evacuations after the storm had passed, instead of him having to call for Greyhounds.

This is, of course, all water over the dam in the most literal sense, but given all the finger-pointing going on, it's hard to ignore this issue. Had more people been evacuated, as they should have been, before the storm hit, conditions in the city would have been better, and relief services less stressed, afterward. [My emphasis]