Now we know. We are on our own. It's every man for himself.

Hurricane Katrina has shown us that the country is no more prepared for a terrorist attack today than it was on Sept. 11, 2001. The question is what to do with that information.

How do we protect ourselves and our families, knowing that the government is probably not going to protect us? A Sept. 11 front-page story said that Washington "lacks a comprehensive way to tell people what to do in a state of emergency, especially a terrorist attack with no warning" -- this at a time when a terrorist attack is considered imminent.

"The next attack is more likely to be catastrophic," says Stephen Flynn, a terrorism expert at the Council on Foreign Relations. The terrorists will have spent the years since Sept. 11 rebuilding their attack structure, he says, and he lists dirty bombs and assaults on chemical facilities near large population centers and on the food supply, as the next likely forms of terrorism. Hurricane Katrina has "created an incentive" for a terrorist attack, Flynn believes, and "the Department of Homeland Security is not ready for prime time." Anyone who is not prepared for an attack, he continues, diminishes the capability to help people who really are in need and becomes part of the problem.

So what is Flynn doing?

"I've got my bottled water, a generator, canned goods, a radio and flashlight and two numbers to call."

More than two years ago I wrote a piece telling people to be prepared ["We Can Do Better Than Duct Tape," op-ed, Feb. 13, 2003]. Preparedness now is more important than ever. We have seen in New Orleans what happens when people are not prepared.

Here's what you need:

Water and food for at least a week. A radio and a flashlight with batteries. Contact numbers for the family, emergency routes and a full tank of gas (if you can afford it). First-aid kit, backpacks with medicine, the antibiotics Cipro and doxycycline (don't tell us to wait and get a prescription from the doctor after the anthrax attack. The doctor won't be in, and the drugstores will be closed). And yes, plastic sheeting and duct tape. An N95 mask, which sells for a few dollars at most drugstores, could save your life.

Here's why you need to do all this: We cannot count on the government to help us, and when it can, it will have limited resources. A segment of the population will always be incapable of preparing. Every person who prepares means one less person to rely on government resources, so it is irresponsible and unpatriotic not to prepare if you can.

More than that, it is stupid. Not being prepared puts your life and the lives of your family at risk. At the same time, if large numbers of people are unprepared, those who have prepared could have their resources taken from them, possibly at gunpoint. Therefore, the less prepared the population is, the more dangerous the situation will become as people grow desperate.

As citizens, we can and must do something else too: Complain.

We have to demand better preparation from our government at every level. Part of our social contract with our government is that it will provide for and protect us. It has failed miserably in New Orleans, when it had warning of the impending disaster, and it will fail even more miserably when we are hit by terrorists who give no warning.

Monica Schoch-Spana, a senior associate at the Center for Biosecurity of the University of Pittsburgh Medical Center, says, "We have had years to prepare, and we are no better off." But part of our civic duty, she believes, is to advocate for collective security.

"Where is the public cry for the function of government that is part of the social contract?" she asks. "This is not about going to Home Depot and getting duct tape and plastic. This is a shame on our culture."

For many people, preparedness is "not a matter of personal choice," Schoch-Spana points out. She is particularly concerned that hospitals will not be able to deal with a major terrorist event.

"These catastrophic warnings have been made," she says, "and we are ignoring them. We have not decided what constitutes public preparedness."

We, as a society, must demand a plan, and we must demand that the plan be practiced over and over, for many scenarios, including chlorine tanker attacks, dirty bombs, chemical and biological attacks, fire bombings of subways and trains, even nuclear attacks.

Ralph Gomory, president of the Alfred P. Sloan Foundation, a nonprofit institution with a long-standing interest in biodefense, says people need to "prepare and raise hell." He calls an unrehearsed plan "nonsense."

There should be neighborhood and block organizations across the city. There should be designated places for people to go. There should be methods of disseminating information. There should be community organizations and churches collecting supplies for those who cannot afford to protect themselves. And all of this should have been done by now.

Right after Sept. 11, when I was terrified of another attack, Bob Woodward said to me, "I wouldn't worry about anything happening now. I would start worrying three or four years from now."

Well, that's where we are today. What are you going to do about it?

-- Sally Quinn

is a reporter for The Post.