Imagine this scenario: with the best evidence at their disposal, the leaders of the medical community decide that a new strain of flu, which is killing thousands of people in Asia, will almost certainly spread and cause a major worldwide epidemic. Nobody can be sure where or when it will break out, but it has the potential to kill millions. Other countries' health establishments look at the available data and agree... this could be a really bad one, maybe 1918 over again.

Acting on the basis of information from the world's experts, the President decides to produce a vaccine and to advise everyone to get immunized. Fortunately the technical expertise exists to do so, and there is enough time to get it done. People heed the urgings; most get their shots.

But no epidemic develops here. It was a false alarm. Medical science knows a few things about the influenza virus, but the little pathogen still holds a lot of secrets. We didn't need to go to all that expense and trouble after all. The vaccine was put to good use in Asia; it stopped most of the dying there. People can now go on with their lives, and that's certainly a good thing for them.

But we didn't need to do it, at least not for our own safety. It cost a lot of money in a time of deficits. Worse yet, numbers of people had bad reactions to the vaccine, and some of them died. Given the tens of millions who were inoculated, even a small rate of fatalities produced hundreds of deaths. By sponsoring the vaccine, the President caused American lives to be lost.

Critics appear. A few say, well, we were wrong, and that shows that we need to do more research into influenza than we already have, and certain restrictions on that research need to be lifted. And we need to examine how we made the decision, so we can do better next time. We remember our fellow citizens who were lost, and we bless their memory,  and we vow to care for those they left behind.

Some others take a different tack. They say, flu? There was never any flu. And even if there was, it was no threat to us. So why did the health establishment and the President make us all get shots? They lied to us! For their own nefarious purposes, no doubt. Someone must have made a lot of money on that vaccine. Someone connected to the Administration. People are dead. There was no need for it. The President must pay for this betrayal.

This group rallies around a candidate who says what they want to hear, even if he doesn't really believe it himself, and this candidate wins the next election.

After some time passes, there is word of a new epidemic. It's in Africa this time, and it's a new virus, not the flu. They're calling it Ivorian Hemorrhagic Fever. People are getting sick and then bleeding to death. Thanks to the miracle of modern molecular biology, we can identify it quick as you like, even though we've never seen it before. With luck, we can start working on some drugs that might work, maybe a vaccine.

But that would require a commitment of money that we just don't really have right now, and there's the danger the drug will have side effects. Or, maybe the vaccine will make people schizophrenic or something years later, who can tell?  There are always hazards with new drugs, and proper testing can take years. Remember what happened last time? They lied to us then, that's what people know now. There wasn't any flu, and people died. Remember that?

Then someone will get on a plane without knowing he's sick, and fly to America. He will cough a bit while waiting in line at customs at JFK, and people here will start to die, and not in a nice way, either. Soon everyone will want to know, why the heck didn't we stop it, and why aren't we ready to treat it, and in God's name why isn't there a vaccine, and why didn't the government know this was going to happen?

Or maybe they did? That's it, they knew! Why didn't they stop it in time?

End of scenario.

There is still no evidence of large quantities of WMD in Iraq. But of course everyone, everyone, thought Saddam had them. There had been WMD before (if you don't think so ask the Kurds) and Saddam was certainly acting as if he still had things to hide. And even while David Kay was telling us he couldn't find any, in the next breath he was saying that there were programs and facilities still intact which could make them. In fact, the place was even scarier than he thought it would be, because there was all this expertise and material all out of control. Who knows what representatives of what potential terrorist groups were flittering around hither and yon, making contacts and spending money?

The world is still a dangerous place. It's less dangerous than it was last year, now that Saddam is deposed. Ghaddafi has seen the light and given up his nuclear weapons program. Pakistan's nuclear bomb export industry has been unmasked. But there will be other threats, just as there will always be new diseases popping up. There are millions of people in the world who, for their own twisted reasons, would just as soon see us dead. A small but significant number have the resources and the will to act on those wishes.

And if one of them someday gets his hands on a nuclear bomb or some genetically altered smallpox, and an American downtown vanishes under a mushroom cloud, or our society breaks down under the stress of millions dead from a contagious disease, what will they say, those who now say, 'Bush lied'?

We know what they will say. They will say, 'Why wasn't this prevented?' What they will never say or acknowledge is that their ravings and their election slogans weakened the ability of the President, whether this one or future ones, to preemptively deal with such gathering threats.

There is much to honestly criticize in the actions of this Administration in the War on Terror. While we must always keep in mind that much happens behind the scenes and we are not privy to everything, questions can be honestly asked about the preparation for post—war Iraq, the Saudi connection, the alleged failure to do enough to safeguard Soviet nukes, and the quality of our intelligence services. And if you care, I personally disagree with many of President Bush's domestic, trade and fiscal policies. But those who want to be President, and who try to achieve that goal by cynically questioning the veracity of the Administration's effort to protect us from the evil we saw so starkly on 9/11/01, are undercutting the ability of our current and future leaders to keep us safe.

Their behavior is no less than a threat to the future of my country and my children. I will never vote for them, never, and I will never forgive them. They should be ashamed.

Jack Birnbaum is a physician and the author of the recently published novel 'The Winter of Visions and Forgetting.'