The baby boomers are gray and nearing retirement, the nation is involved in two conflicts abroad, the economy is moving into a new, uncertain phase, officials are worrying about terror strikes at home, there’s a huge debate about civil liberties raging in the country, scientists are concerned about eroding American superiority in technology, and what are we doing in the first week of May 2004? We’re fighting over Vietnam. Again.

The war ended almost three decades ago. Lyndon Johnson is dead. Richard Nixon, too. William C. Westmoreland is 90 years old, Eugene J. McCarthy is 88, Robert S. McNamara will be 88 next month, Jane Fonda is about to turn 67. The United States lifted its trade embargo with Vietnam a decade ago.

This is the war that never ends. We think it fades away, and then it comes back again. In pieces I’ve written over the years I’ve personally pronounced Vietnam over, politically and emotionally, twice — first when the United States and its allies defeated Iraq in Gulf War I and then, again, when Washington established diplomatic relations with Hanoi in 1995 — only to be proven wrong both times. So much for my powers of observation.

The war’s not over. It may never be.

“We’re just haunted by Vietnam,” says Stanley Karnow, author of a popular history of the war. “It doesn’t go away.”

Indeed, this war has an astonishing half-life. Do the math: If the ripples from the Civil War had lasted as long as the ones from Vietnam, the election of 1892 would have been about slavery. It wasn’t. It was about economic growth and economic justice. It’s plausible to argue that World War II echoed for as long as Vietnam does — Europe, after all, was still divided in 1974, which was 29 years after V-E Day — but that was a world war, and besides, no one in 1974 was arguing about American motives in a conflict against Imperial Germany, Italy and Japan.

There was consensus at home over that, and besides, we were too worried about Watergate.

But this very month, the two sides in the first American election conducted in the age of terror are bickering over who served and who didn’t, whose medals were or were not tossed over a fence and whose Reserve records are or are not exculpatory. This week, Sen. John F. Kerry is starting an ad blitz that will deal in part with this very subject. He’s not doing so in a vacuum. His rivals have been talking about his war record, and his anti-war record, for days.

This most recent Vietnam retrospective tells us as much about the way things are as it does about the way things were. Vietnam has an unusual resiliency — nine of the last 11 elections have had a strong Vietnam element — but its prominence in this campaign is striking.

“Part of this is healthy,” says Thomas J. Vallely, a Marine in Vietnam who now directs the Vietnam Program at Harvard’s Kennedy School of Government.

“The campaign aspect — whether Kerry will vote like Jane Fonda and whether the president skirted his duty — is almost beside the point. But the intellectual side — whether this war is like Vietnam — is helpful. It’s actually useful to wonder about dominoes again. Pakistan is a potential domino. Iraq is a potential domino. And if you think the main lesson of Vietnam is hubris, we have to remember that hubris is dangerous. We also have to remember that we are again in a place that we don’t understand.”

True enough. But the value of the Vietnam lessons is limited, and one of the lessons of Vietnam — where the United States wrongly applied the lessons of the Munich Conference of 1938 — is that not every lesson can be applied to every situation. You may have to read that sentence twice, but I suppose that’s appropriate. Everything about Vietnam gets repeated.

But this preoccupation with Vietnam tells us that the moral of one of our most powerful folk tales is not yet clear. It might be that a reluctant nation fighting a war reluctantly cannot prevail. It might be that wars without well-defined goals will reach poorly defined conclusions. It might be that a war without a national consensus produces a result without a national consensus. It might mean that a war without an exit strategy produces an exit without a strategy. It might mean that a struggle for other people’s freedom isn’t winnable, or that people can only win their own freedom. It might mean all of those things, or none of them, or some combination. But we feel no similar ambiguity about World War I or World War II.

Perhaps the most fascinating episode in this Vietnam reprise has been the exchange of fire at Westminster College in Fulton, Mo. There, at the place where Winston S. Churchill delivered his “Iron Curtain” speech on March 5, 1946, Vice President Dick Cheney attacked Kerry’s war record, only to have Kerry, a decorated veteran, respond in kind. It was not a particularly illuminating episode, but it was enough to prompt me to go back and re-read Churchill’s original speech in its entirely. Do the same thing, and I bet you pause at these four sentences:

The United States stands at this time at the pinnacle of world power. It is a solemn moment for the American democracy. For with primacy in power is also joined an awe-inspiring accountability to the future. If you look around you, you must feel not only the sense of duty done, but also you must feel anxiety lest you fall below the level of achievement.

One of the achievements of Churchill’s war is that he and his allies were able to bring it to a close. We haven’t succeeded in doing that about Vietnam.

David Shribman is a columnist for Universal Press Syndicate.