Incompetence has been the word used the world over to describe the rescue from Hurricane Katrina. The US Federal Emergency Management Agency and its parent, the new, giant Department of Homeland Security, did not respond fast enough. Worse yet, President George W. Bush did not respond fast enough. This, the commander-in-chief who wages lightning wars?

The critics are right on one point. There was hesitation. That hesitation at times represented incompetence. But it was also something else: what we might call the Federalist Pause.

The Federalist Pause is that little intake of breath, that clearing of the political throat that American leaders instinctively demonstrate before plunging forward. Mr Bush provided a classic demonstration of the pause last week when he considered invoking a little-known law, the Insurrection Act, to take over Louisiana - and chose not to, out of deference to the authority of Kathleen Blanco, the governor. The pause can be lethal. It may have been last week. But there are reasons for it.

The habit of the pause goes back more than two centuries, to the founding fathers. Even centralisers among them did not see Washington's role as handling events like Katrina. Towns, counties or, at the very highest, states were responsible for citizen safety. Washington could not intrude uninvited.

Sound principles were behind such federalism. The first was local sovereignty: a rescuing Washington was a threatening Washington. There was also the matter of moral hazard: if localities knew they could count on Washington, they would not take care to stay out of harm's way. Most Americans, moreover, nursed a suspicion that Washington's bureaucracies might not do important work as well as local authorities did.

There was also a fear of the opposite: that an efficient centralised government would prove so compelling as to make its expansion impossible to check. Inefficiency, the bungling of co-ordination efforts, might even be a good thing, if it slowed the rise of tyrants. Whenever confronting emergency - from uprisings of native Americans to epidemics of influenza - officials thought twice about whether the rescue job was truly Washington's.

The example of federalism in action most relevant to Katrina was the Mississippi flood of 1927. The flood covered whole states. Waters raging up to 100 feet high drove 1.5m from their homes. The flood destroyed 2m acres of crops, the region's livelihood.

President Calvin Coolidge paused - and decided the flood was not the president's job. To manage the rescue he sent Herbert Hoover - his own version of Rudy Giuliani, who got New York back to work after the attacks of four years ago. But the Mississippi rescue was different from the sort expected today. Hoover, the commerce secretary, had no giant government cheques. His role was more that of broker than funder. He negotiated among states; his Red Cross drive raised $15m. When Hoover needed something, he found donors or simply commandeered goods. Sawmills along the river hammered out 1,000 rough wooden boats. Outboard motor manufacturers supplied 1,000 motors (of which only 120 were returned). The Pullman Company provided Hoover with his own train cars - including a dining car - so that he might inspect his refugee camps.

The 1927 rescue was greatly flawed. Bigoted rescuers treated blacks as second-class citizens or worse. Blacks found themselves stranded on levees. Malaria and typhoid plagued camps. Still, the rescue provided a model of leadership that could have been useful this time around. Hoover became so famous he claimed the presidency with ease the following year.

Today the US federal government plays a much larger role on the national stage than it did in 1927. Yet some would like to see it even more powerful. They blame, in effect, the Federalist Pause for the hurricane deaths, pointing out that, even now, Fema is not supposed to be a "first responder" - it must wait for an invitation to act. Governor Blanco and Washington were unable to co-ordinate and, if Washington controlled everything, there would be no need for co-ordination.

If the system were more centralised, Michael Chertoff of the Department of Homeland Security or Michael Brown of Fema would have acted faster. Or so the argument goes.

Every philosophy has its weakest moment. Federalism's worst moment is the natural disaster. One could say that Katrina, with its body bags, is proof that Washington must become stronger in future. Still, to argue that Mr Bush should have jumped into New Orleans like a crisis dictator is to superimpose a European sensibility on an American crisis. Mr Bush is commander-in-chief when it comes to war but, when it comes to disasters, he is still only a chief executive in a system of checks and balances.

Observing Louisiana, one can hear the counter-arguments. Because the Feds were responsible for the levees, in effect, no one was. If there were no Fema to call, Ray Nagin, the mayor, might have loaded people on to his own city's buses and moved them out on the Sunday before the storm.

As for the value of increased federal bureaucracy, a bureaucracy with a mandate larger than Herbert Hoover ever dreamed of - the Department of Homeland Security - is getting poor marks for its Katrina rescue. New Orleans is a tragedy, but a larger tragedy still would be to sacrifice federalism in its name.

© Copyright 2005 Financial Times