Two years ago, the Department of Homeland Security exploded a mock dirty bomb in Seattle. It was the first major test of the federal government's supposedly improved disaster-response capabilities since September 11, 2001, and the exercise, which cost $16 million and involved hundreds of local emergency workers as well as a large cast of frantic "victims," was widely pronounced a triumph of interagency coordination.

The Seattle Times, the day after the mock disaster concluded, ran the headline, "Emergency Exercise Seen as a Real Success."

If the federal government learned how to respond to a devastated city from that exercise, it didn't show in its response to Hurricane Katrina. As many experts noted while watching the chaotic aftermath of the hurricane, the impact of this natural disaster bore many similarities to the predicted impact of a terrorist dirty bomb being exploded in a major American city—a dense urban environment was rendered uninhabitable, there were a huge number of deaths and injuries, there was mass panic and confusion, and there was a desperate need for a quick response from the federal government to bring the situation under control.

Although the positive pronouncements after the 2003 Seattle exercise received a lot of press attention—as have all of the federal government's boasts about its new preparedness for urban disasters since 9/11—less noticed was a Wall Street Journal article published five months after the Seattle exercise.

The Journal found that an internal report prepared by the Federal Emergency Management Agency expressed alarm at the communication failures and chain-of-command confusion exhibited during the Seattle exercise, concluding, "Fortunately, this was only a test." If a real city-disabling incident were to occur before procedures were improved, the FEMA report said, the results would be "unacceptable."

Sound familiar? That's the word President George W. Bush was forced to utter last week as it became clear that the federal government's response to the disaster in New Orleans was, to quote the president, "not acceptable."

One of the lessons learned from the Seattle exercise, which also included a Chicago component that tested the government's response to a near-simultaneous biological attack there, was that people would not respond well to being quarantined in the event of a frightening catastrophe. As the Christian Science Monitor reported, even before the 2003 test the government knew of a long history showing that quarantines "can spark civilian violence against authorities," and warned against keeping people cooped up during frightening disasters.

The refugees packed into the Superdome and other wretched spots in New Orleans, while not suffering from a biological attack, were essentially quarantined, and in the worst possible way—unnecessarily, with not enough food and water, insufficient crowd control, and no clear timeline for release. Predictably, the social order broke down, and violence against authorities, in the form of gunshots being fired at rescue helicopters and hospitals, was reported throughout the city.

The month before the Seattle exercise, former Homeland Security Secretary Tom Ridge urged Americans to individually prepare themselves for riding out catastrophic urban terrorist attacks. In what was meant to be an improvement on his much-ridiculed advice that people stockpile duct tape and plastic sheeting, he emphasized basic measures, like storing bottled water and enough nonperishable food for three days' survival.

I ignored Ridge's warning, figuring: I live in America, the richest and most powerful nation in the world. If something ever happens that disables my city to the extent that I can't get water or food, I will either be dead or the cavalry of the federal government will soon be coming to rescue me.

Watching the government's response to the hurricane and flooding, I am feeling as if that idea of a federal government prepared to help me in case of a huge catastrophe is a fantasy I can no longer afford to indulge. I've been thinking about how I would most quickly get out of town if something happened, so that I could avoid the unchecked social disintegration that killed people in New Orleans. And I'm preparing a list of items to put in my disaster kit. At the top are the essentials the government, unbelievably, was unable to get to the people stranded at the New Orleans Superdome for nearly five days: food and water.