Americans under 40 can be excused if they think that the presidential campaign went a bit nuts recently. After all, why has campaign coverage been dominated by a war that ended 29 years ago, even as a dozen Americans were dying and more than 130,000 fighting in Iraq?

Well, kids, welcome to an encore presentation of our Second Civil War. The anger and viciousness of the Swift boat debate provide just a brief reminder of how Vietnam divided our nation for a decade. One of my best friends in high school wrote me a furious letter in 1966, saying that since I was then in Vietnam, I must be a war criminal, and he would never speak to me again. And he never did.

Since most of the media covering the election remember the Vietnam era, it fascinates them still, and thus they tend to overdo it. For Americans of a certain age, Vietnam is the war that will not die -- until they do. On one side are those who believe that Vietnam was a war we could have won if not for the congressional doves, the left-wing press and the long-haired antiwar demonstrators. On the other are those who turned against the war in the mid- and late-1960s and never forgot the drama of those days.

"Vietnam cleaves us still," President Bush said so eloquently in his inaugural address. Of course, that was George Herbert Walker Bush, in 1989. He worked with men such as John McCain and John Kerry to try to end the divisions Vietnam had caused in our society. Not so for the Swift boat veterans -- the group that the current President Bush refuses to repudiate -- who have revived the sort of charges that were such a bitter part of the Vietnam era itself.

Anyone who was in Vietnam knows that "the fog of war" was more than a cliche. I remember visiting destroyed hamlets in the lower Mekong Delta in the mid-1960s, sometimes only hours after the fighting had stopped, and hearing different versions of what had just transpired from survivors who had been right next to each other during the attack. Is it any wonder that memories would differ on details of events 33 years ago? But the timing of the attack by the anti-Kerry Swift boat veterans is rooted in politics and personal vendettas; on examination their charges are sloppy and self-contradictory.

I did not know John Kerry in Vietnam, but I knew the area he was in, having served in the same area as a civilian. I've talked to him often about Vietnam in recent years, and there is no question in my mind that it was the defining experience of his adult years, just as it was for me and hundreds of thousands of other Americans, including those now attacking him.

His personal saga embodies the American experience in Vietnam. First he was a good hero in a bad war -- a man who volunteered for duty in the Navy and then asked for an assignment on the boats that were to ply the dangerous rivers of Vietnam -- when most of his college-educated contemporaries (including George W. Bush and Dick Cheney and Bill Clinton) -- found easy ways to avoid Vietnam. Then, carrying shrapnel in his thigh, he became an eloquent but moderate member of the antiwar movement.

John Kerry introduced his Vietnam record into his campaign because it is a central part of who he is. But stirring up the embers of our Second Civil War was not his intention. Younger people I have talked to tell me that this past week it seemed to them nothing more than a silly, irrelevant argument about a distant war; to a certain extent, I agree. All those who served in Vietnam put their lives at risk, and at this distance from the war they all deserve respect. Those of us who survived should show younger Americans that we learned something from the war; John Kerry clearly did, but the same cannot be said of his Swift boat critics. To have a sterile debate about the minutiae of his service, when the basic facts of his heroism are undeniable -- and while Americans are again in a war that seems to have no exit -- is particularly grotesque.

Watching this debate over Vietnam while a new generation of Americans are risking their lives in Iraq, I had a sudden vision: a television talk show in April of 2025, on the 50th anniversary of the end of the war in Vietnam. After being pushed into the studio in wheelchairs, the ancient veterans suddenly come to life with still another round of name-calling. How long before the lessons from Vietnam can be absorbed into our national life without resurrecting a civil war that cleaves us still?

The writer, a former U.S. ambassador to the United Nations, served as a civilian in Vietnam for three years in the 1960s.