Where were the smiles, the flowers? We'd expected, in a modest way, to be greeted as liberators.

This was many years ago, Chu Lai, South Vietnam, 1966, in one of the early disasters of The United States' post-World War II attempts to fight wars for virtue. People in the villages refused to meet our eyes, and they only smiled if they were selling us something.

How disappointing. The war was young then, and so were we, but not so young that we hadn't seen newsreel footage of the cheers from the giddy urchins of Naples, the French doing their tiptoe waves. But not the Vietnamese. It seemed that in Chu Lai, at least, the beneficiaries of our liberation and largesse hated us, or were too scared to show they liked us.

But why? Weren't we fighting a war of liberation, another good war in the American tradition of good wars? Wasn't my Marine civic action team giving candy to children, the same SweeTarts you could buy in American movie theaters?

The giveaway lasted two days.

"SweeTart numbah ten!" shouted the kids who swarmed our truck on the second day. "Numbah ten" meant the worst. They flung the SweeTarts back at us. We flung them back at them, no doubt losing a heart here, a mind there. The Battle of the SweeTarts. At the end of the day you'd have to say we lost it, another case of American virtue unrewarded.

The good war, the virtuous war. We believe in it. We have to believe in it or we wouldn't be Americans.

As John Updike wrote: "America is beyond power, it acts as in a dream, as a face of God. Wherever America is, there is freedom, and wherever America is not, madness rules with chains, darkness strangles millions. Beneath her patient bombers, paradise is possible."

The United States doesn't fight for land, resources, hatred, revenge, tribute, religious conversion - the usual stuff. Along with the occasional barrel of oil, we fight for virtue.

Never mind that it doesn't work out - the Gulf of Tonkin lies, Agent Orange, waterboarding, nonexistent weapons of mass destruction, the pointless horrors of Abu Ghraib, a fighter plane wiping out an Afghan wedding party, our explanation of civilian deaths as an abstraction: "collateral damage."

Just so. We talk about our warmaking as if it were a therapeutic science - surgical strikes, precision bombing, graduated responses, a homeopathic treatment that uses war to cure us of war. We send out our patient bombers in the manner of piling on blankets to break a child's fever. We launch our missiles and say: "We're doing it for your own good."

After World War II, I was taught in school that humankind, especially Americans, hate war and love peace. The United Nations rose on New York's East River, a foundry beating swords into plowshares. We renamed the Department of War as the Department of Defense. We had Atoms for Peace, CARE packages, UNICEF boxes at Halloween and the Berlin Airlift instead of a war against the Soviet Union.

The problem here is that humankind doesn't hate war, it loves war.

What better explains all of recorded history with its atrocity, conquest, pillage and extermination? If we hated wars, we wouldn't fight so many of them. Our love of war is the problem. War is an addiction, maybe a disease, the chronic autoimmune disease of humanity. It erupts, it subsides, but it's always there, waiting to cripple and kill us. The best we can do is hope to keep it in remission.

And yet Americans still believe in the idea of the good and virtuous war. It scratches our Calvinist itch; it proves our election to blessedness. Thus God is on our side. Strangely enough, though, we keep losing. Since World War II, we have failed to win any land war that lasted more than a week: Korea (a stalemate), Vietnam, little ones like Lebanon and Somalia, bigger ones like Iraq and Afghanistan. Ah, but these were all intended to be good wars, saving people from themselves.

The latest target of opportunity for our patient bombers is Syria. The purity of our motives is unassailable. We would fire our missiles only to punish sin, this time in the form of poison gas. No land grab, no oil, not even an attempt to install democracy.

Oscar Wilde said: "As long as war is regarded as wicked, it will always have its fascination. When it is looked upon as vulgar, it will cease to be popular." He didn't foresee a United States that would regard war as virtuous.

What a dangerous idea it is.

Henry Allen won the Pulitzer Prize for criticism in 2000. Now retired, he was a Washington Post editor and reporter for 39 years.