Mieville brings this up as a part of an attack on Nagin, cataloguing his failures to prepare for the storm, and pointing out that he was a lifelong Republican who switched parties to run for Mayor of NOLA. I suppose Nagin's "You're shit out of luck" message to the poor could have been a reluctant admission that he simply hasn't been given the funds to prepare an evacuation. Still, it doesn't look good.
As I have said in other forums, I like Belle's suggestion, which I reprint in full:
The thing about captaining the ship of state is this: if you lose a good part of your fleet, you get relieved of your command. Even if you did all you could---but especially if you didn't. Even if you made a reasonable guess about the future that turned out wrong---but especially if you ignored prescient warnings from that lowly lieutenant. Even if a damn meteor strike holes your ship without warning. What about all the Democratic mayors, senators and governors? Yeah, kick their asses to the curb too. Everybody, up and down the line. Enough failing upwards, enough medals of honor. Once things get stabilized, I want everybody to fucking resign their command, because this just wasn't right. Come on: WWHD? (What would Hornblower do?)
In fact, I go a step further. People like Nagin should merely resign their posts. But the President of the United States, should, as a matter of honor, commit ritual suicide in response to this disaster.