In Jared Diamond's book The Third Chimpanzee, he points out that we share about 98 percent of our DNA with chimpanzees, which is not much greater than the difference between chimps and bonobo pygmy chimps. He also postulates that human behavior is merely an elaboration of basic primate behavior. Bands of chimps hold a territory, and the young males instinctively patrol its boundaries, keeping watch for leopards and the young males of adjacent bands who sneak in and steal bananas. When that happens they beat them up or kill them if they can.

I've found that a great deal of puzzling human behavior becomes perfectly clear if one thinks of our species as chimps with nukes.

All of our statecraft and "military science" is an elaboration on the theme of stealing and protecting bananas. We just do these things more intelligently than chimps, which is where the real danger lies. A behavior pattern that results in a dead chimp may make sense. One that results in a dead planet does not.

There is probably no one of average or better intelligence who does not believe that war, the way we wage it now, is insane. Yet we keep doing it, blaming each other, captive of our primate genes.

This article is not an argument for or against war. Winston Churchill was right that slavery is worse than war. Dishonor is worse than war. Lots of things are worse than war. What it's an argument for is leaders who know this first hand.

Harry Truman fought in France in World War I. Kennedy, Johnson, Nixon all took the oath and wore the uniform. Even Reagan did that, though he only made training films in Hollywood as a captain in the Signal Corps.

FDR didn't serve, of course. He was wheelchair-bound. But his son Elliott served as second in command of a Marine Raider Battalion. There is no more hairy assignment than that. From a geopolitical standpoint, it makes no sense to have the son of the head of state subject to capture by the enemy. Young Roosevelt undoubtedly wanted to be in the war, but if his father allowed it, this must have been, at least partially, to make an egalitarian statement to the country.

Vietnam was not a popular war. Getting out of it replaced baseball as the national pastime in the early '70s. Though his father had served in World War II, George W. Bush skated in the Texas Air Guard. Cheney, Wolfowitz, and Pearle had deferments. Only Rumsfeld was a Navy pilot, prior to Vietnam.

These are not bad men. But if you haven't seen your best friend's face turn to red goo before your eyes, or watched a child die because you made a simple mistake throwing steel around at supersonic speed after three days without sleep -- well, if you haven't done that, then, by definition, when it comes to war, you don't know what you're talking about.

In March of 1964 I was the "Senior Advisor" of a patrol of four Americans and a platoon of Jarai Montagnard tribesmen. We were out hunting for the entire population of a Jarai village that the Viet Cong had kidnapped to use as slave labor in the jungle. It was a small patrol, put together quickly. Frankly, we knew that the chances of finding the village were almost nil, but we had to make a good-faith effort or risk losing support from the other villages.

We had mounted the patrol so quickly that there was no interpreter available. I was "advising" the Montagnard "commander" with hand-and-arm signals and about 150 words of survival French I had learned on Okinawa. Ksor Yul, the platoon leader, also remembered some French from his service in the Indochina War. Some of them were the same words.

Oddly, this worked well enough. We couldn't discuss philosophy, but we could patrol.

About noon of the second day we crossed the Li Piao River, Ayunapa in Jarai, and moved parallel to it, hidden in the bush. Most of the central highlands was dense jungle, but this was open and parklike. Then my left flank guy signaled that he had spotted something. It was three Bahnar tribesmen, young boys working in a rice field by the river. I wanted to ask them if they had seen our VC and their group of villagers. We moved around them in the jungle, surrounding them on three sides, with the river on the fourth. The river was three-feet deep and more than a hundred feet across. No one but a fool would try to escape across it under such circumstances. A fool or a kid.

The boys broke for the river. I charged after them, into the water, wearing 40 pounds of gear and clothes that soaked and dragged me back. It was like running in a nightmare. My Americans fired warning shots. We had taught our Jarai a lot, but not about warning shots. They had been at war with the Bahnar, on and off, for about 900 years. They shot to kill. I screamed, "No g'pow! No g'pow!" g'pow being Jarai for gun. Probably the only thing that saved two of them was that my troops had to shoot wide to avoid hitting me. But they hit one of them and blood ran down his back as he ran. The other two scampered over the bank and into the jungle on the other side, but this kid wavered and fell by the river.

He was bleeding from a head wound. We bandaged it, but that didn't stop the bleeding. I didn't have an American medic, but we pulled a can of blood expander out of our Montagnard medic's pack. He had filled it with aspirin.

Then a sniper opened up from across the river. I took a squad, moved back into the jungle again, crossed the river out of sight around a bend, and moved through the jungle toward the sniper. None of my squad would take the point, so I did. I knew the sniper, if we found him, would have the first shot. I have great confidence in my marksmanship. If he missed me on the first round, I'd kill him before he got off a second. That's a big if, and I was more scared than I've ever been.

But the sniper had bugged out.

I crossed the river for the fourth time. When I reached the bank, I stood and watched the boy die. And I watched him die in my dreams every night for the next ten years. I will probably see him die on the day I do, and I will still grieve for him. I bear responsibility for his death, and I never knew his name.

In war, every digit of every casualty figure has a story like that attached to it, and every one is a tragedy for a family and for the comrades of the dead. We have objectivised language in the military. Dead babies are "collateral damage." Dead teenagers, last May's bright and hopeful high school grads, are "friendly" or "enemy casualties." There's a reason for the language. As long as you can think like that, you can keep fighting. But in the dark of the night, for all the long years that follow, they're just dead kids, and the tears that you've managed to postpone come at strange and inappropriate times.

But our leaders will not have these troubles with their dreams. Somehow this country is now run by people who think they're too good to fight for it.

This was dramatically brought home to me a few years ago when I was an editor in New York publishing. I learned that the editor-in-chief of our literary imprint had actually known James Jones, the author of From Here to Eternity, a book I've read nine times. So I talked to her about Jones, and in the course of the conversation she mentioned that I was the only Vietnam veteran she had ever met.

My God, that was stunning. This woman was in the upper reaches of New York society. Her husband tried cases before the Supreme Court. She'd had Caroline Kennedy Schlossberg and her husband to dinner the previous week. But she had never, neither socially nor professionally, knowingly met a Vietnam veteran.

But when our offices were moved in a corporate takeover, I stood in the halls and played Where-was-you-at? with the moving men. "Were you there for Tet?" "Were you in the Ia Drang?" Yes, they were.

About ten years ago the armed services pruned all the Vietnam vets they could from their ranks. The 'Nammers had had that experience of being sold out by the people they risked their lives for, their lives expended needlessly by people who did not go and did not send their children. For the most part these men were still brave, still willing, if necessary, to die for freedom. But they were entirely too prone to ask the question, "Is this trip really necessary?"

It would probably be politically impossible to invade Iraq with an army of draftees. With the all-volunteer Army we are spared those embarrassing questions about inequality of sacrifice.

I have heard and believe that during the entire course of the Vietnam War the son of only one congressman served. But those congressmen who did not send their sons, and did not send the sons of their college-deferred big contributors, voted with the Tonkin Gulf Resolution to send the sons of their less-affluent constituents. This is as grand a betrayal as I can imagine.

So we are now led by people who did not serve, and whose children do not serve. There is no Lieutenant Rumsfeld waiting for the new gas masks for his platoon. There is no Navy pilot named Bush in this generation. Somebody's daughter will die, but it won't be Barb or Jenna.

It's interesting to me that no Vietnam vet has achieved the office of President of the United States. Those who have climbed as high as the senate have done so under special circumstances. One wonders if John McCain would have been elected if he'd merely been a fighter pilot and not a POW. One wonders if Bob Kerry would have gone so far if he'd not lost a leg. But both of them know the full horror of war. I'd be far more comfortable if the decision to invade or not invade Iraq were being made by such a man. They don't see "collateral damage." They see dead babies.

Since Vietnam, I don't think America trusts her military anymore. This is something of a mistake. There were next to no congressmen's sons in Vietnam, but every three or four weeks I'd pick up a Stars and Stripes and read where Lieutenant So-and-so, the son of General So-and-so, had been killed leading a Marine platoon. The military is probably the only segment of our society left that has that sense of noblesse oblige.

Saddam's military capabilities compared to those of the United States are almost laughable...unless we're right, and he has poison gas and biological agents and uses them. We'll still "win," but no one will be laughing because nothing will be funny.

The notion that we, the United States, can create "a stable democracy" in the Middle East strikes me as hubris of the highest order. But it's possible. We managed to create fairly stable, fairly democratic regimes in Japan and the Philippines after World War II, and they're still functioning more or less in that mode. So maybe this will work. But it's a very long shot. I'd just feel ever so much better if the people making the decisions carried the same risk as the people carrying them out. The only dogs they have in this fight are their money and their power. Bush won't personally know anyone who dies.

With the British upper classes the oldest son became lord of the manor, and the number two son went to the army, and number three to the church. The British Empire lasted a long time. But I do not think America will long be top nation. The people will lose faith in a leadership that expends America's sons and daughters like used Kleenex but sends its own to Harvard and Yale.

In Rome the Praetorians finally took to installing emperors from among their number. Then came the Visigoths.