I dislike George Bush intensely, and watching him suffer and be pilloried is one of the few plus points of the horrible disaster in the US. However, most commentators doing so seem to be doing so without much of an understanding of How The US Works.
It’s not a country like the UK or France, where central agencies take primary responsibility for everything government does and where the PM can legitimately be blamed for things that go wrong. Rather, it’s a country where the President is generally responsible (although not solely so) for international and interstate matters, and where the states are generally responsible for local issues.
Now, it’s possible that GWB’s actions as President have genuinely impaired the states’ ability to cope with natural disasters – in particular, rolling up flood relief into the Department of Homeland Security and then diverting the money from flood programmes to fund nebulous ‘antiterrorist’ measures. This will take a while to prove, but is legitimate to raise.
However, the mere fact that the flood relief effort in New Orleans massively fucked up is not an indictment of the President. The fault lies partly, and perhaps primarily, with New Orleans’ (Democratic) mayor and Louisiana’s (Democratic) governor.
Side note: some hilariously nasty and gloaty press reactions from around the world are collected here. My favourite is the Frenchman saying "Arrogance is never a good adviser". Meanwhile, the Guardian has some excellent, non-gloaty reporting (indeed, some of the best reporting I’ve seen this year on any subject) on Katrina and its causes, human impact and consequences.