Dave Winer illustrates one of the things I really dislike about political discourse right now: it's utterly detached from historical reality:
It is important to look back, to remember that last year we lost of one our cities, and many thousands of our people lost their homes. A culture died, and our political life is a void until we really feel that. It has never happened in the United States before. We've never lost a whole city like that.
I can come up with a few examples without even trying: Galveston Texas, destroyed in the 1900 huricane. It was a burgeoning center of the oil business; all of that left, never to return. Galveston is now what New Orleans will end up being: a sleepy tourist center.
Then there's the 1871 Chicago fire, which destroyed most of the city. It was rebuilt, of course - Chicago's location guaranteed that.
I could go on, but you get the point. Many people seem to think that the gulf coast devastation is somehow unprecedented, and that the US has never faced a natural disaster of that magnitude. I'm not trying to discount the suffering - but I am trying to put it into perspective. Natural disasters of similar (or greater) scope have hit North America before, and will do so again. In the winter of 1811/1812, quakes from the New Madrid fault actually changed the topography of the region. It was lightly settled at the time, but a similar quake now would do damage that would make Katrina look like a picnic.
Katrina did severe damage to New Orleans and the Gulf Coast, but there's no reason to claim that "nothing like it has happened before". There are plenty of examples, and claims to the contrary do nothing but demonstrate your ignorance.