The big political problem for Bush Co. is that his performance in this crisis is having a multiplier effect. It is giving serious weight and substance to Republican doubts about his competence in other matters and particularly his management of the war Iraq. If the war is far away, people can put it out of their minds. Katrina, however, was an up close and personal look at Bush "in action". What ultimately sealed Bush's fate, I think, were eight simple words, "Brownie, you're doing a heck of a job".
The meme of "Bush incompetence" has taken firm hold and, at this point, there is little that Bush Co. can do to change that image. And for the Republican Party, this poses real problems for the long-term future. Among other things, the "culture of life" issue--the bedrock of Republican culture wars--is in the process of being completely redefined. How many people drowned in nursing homes because help did not arrive in the days after Katrina? (This is the image that FEMA is desperately trying to censor).
Bush is finished, spent as a political force. The question is whether the Democrats will be able to change the national conversation.