I'm not a fan a Bush, I never have been, but I think we can hardly blame him for everything that went wrong with Katrina. F.E.M.A. wasn't prepared for that disaster; how can you blame somebody when the problem could have been there for years. That said, I'm still not a Bush Fan.
People are going to stay no matter how obvious it is that they need to get out. If you moved New Orleans it wouldn't be New Orleans anymore; because its location directly and indirectly influences the City's charm.
There really isn't much debating to be done.
If some incredible feat of engineering can't be performed, then eventually people will have to move, or they will die.