As the battle for New Orleans continued to rage yesterday, Americans’ grief and sympathy were steadily giving way to an intensifying mood of national outrage that carried with it uncertain but potentially wideranging political consequences.

President Bush headed for the Gulf Coast to get a first-hand look at the catastrophe and members of Congress cut short their vacations to pass emergency funding legislation for the relief effort. But across the country, in newspaper editorials and internet chat rooms, there was a mounting sense of anger and disbelief among Americans that one of their great cities had been in deadly disarray for the best part of a week with little evidence of an effective government operation to save it.

After previous man-made or natural disasters — September 11, the Oklahoma bombing, the California earthquake of 1989 — Americans have rallied round their political leaders. But this time may be different.

Some will point the finger at state and local governments. Louisiana politics, and especially that of the “Big Easy”, have been a cesspit of corruption and graft for decades. Politicians, such as the former Governor Edwin Edwards, sentenced to prison four years ago for racketeering, are usually described as colourful.

It is hard to believe that some of the responsibility for the catastrophe that has befallen the residents of New Orleans does not lie with a political culture that has often looked as though it were on sale to the highest bidder. The response of the two most visible Louisiana politicians this week — Katherine Babineaux Blanco, the state’s Governor, and Ray Nagin, the Mayor of New Orleans — has also been underwhelming. The tearful and diffident Mrs Blanco especially has invited unfavourable comparisons with other civic leaders in times of crisis, most notably Rudolph Giuliani, the Mayor of New York on September 11.

But, to be fair, the local leaders have been more victims than authors of their state’s misfortunes. The response of the main organisation responsible for handling the disaster, the Federal Emergency Management Agency, has been widely viewed as inadequate. Katrina was an important test for the agency, its first since it was incorporated into the vast bureaucracy of the Homeland Security Department, and it has not done well. Nonplussed television viewers have been treated to the surreal sight all week of Michael Brown, the agency head, praising the efforts of his staff even as dead bodies decomposed in the summer heat.

Congress will also, rightly, take some of the blame.

Republicans and Democrats in Washington recently agreed to cut federal funding to New Orleans’ flood defences; this at the same time as they were passing a $268 billion (£146 billion) transport Bill that was loaded with pet projects for the districts of members of Congress, such as a $250 million bridge to nowhere in Alaska. There will be broader political consequences. The race question will be thrust centre stage, as Americans ponder the desperate poverty of mostly black New Orleanians that condemned so many to die in the deluge. They were simply too poor to leave.

Others will note the stories of looting, rape and murder in the darkened streets this week and wonder about the lawlessness that seems to characterise so many black communities.

But the man with the most at stake is Mr Bush, whose response so far has been faltering and at times almost insouciant.

It was not a good idea to have him photographed playing the guitar the day the flood-waters rose, nor to have pictures of him looking down from the comfort of Air Force One at the mayhem of New Orleans. That looked grotesquely like an aerial version of what Americans call “rubbernecking”: staring at the scene of somebody else’s misfortune.

Mr Bush’s popularity is already wilting under the heat of setbacks in Iraq and rising petrol prices at home. The gravest danger for him, and Republicans, is that some voters may make a connection between the Katrina futility and the War on Terror.

Domestically, the failure to save more lives in New Orleans will make many Americans wonder how well prepared they are for another massive terrorist attack.

And the flagging support for the war in Iraq could be further undermined by a sense, however unfair, that America’s commitments overseas have left it ill-prepared when misfortune strikes at home. An Associated Press report in New Orleans yesterday captured at least the local mood of anger. It quoted Daniel Edwards, a 47-year-old survivor, who pointed at a dead woman in a wheelchair parked by the side of the city’s convention centre. “I don’t treat my dog like that, ” he said. “I buried my dog. You can do everything for other countries but you can’t do nothing for your own people. You can go overseas with the military but you can’t get them down here.”

Unless Mr Bush can quickly correct that impression, the overriding objective of his whole presidency may yet be another casualty of Katrina.

Times Recommends

• Tehran cannot live up to its rhetoric
• The new unicycle that will ‘change the world’
• We cannot wish away Iran’s bomb