The latest polls this week show Kerry slipping. Among vets he has gone from the mid 40s to the mid 30s, mainly apparently in response to the contretemps over his medals. This is a serious development, though I doubt it's a tipping point, as historian Larry Schweikart contends.

Kerry finally has begun to go on the offense, criticizing President Bush for failing to denounce the so-called Swift Boat Veterans for Truth, who have promulgated the stories about Kerry's medals. Kathleen Hall Jamieson says flatly in the NYT today that it was a mistake for the campaign to wait so long. I agree. And it's not as if the Kerry campaign was caught by surprise. Conservatives have been railing on his military medals for months, as can be seen in this exchange which took place on HNN in April.

Two quick observations and one long one. One, Vietnam has once again roiled presidential politics. (Won't this ever end?) This is the 4th election in which Vietnam has played a central role. In 1964 the Tonkin Gulf resolution gave LBJ a decisive advantage over Goldwater (would anyone want Goldwater at the helm if we were about to get into a shooting war with Vietnam?) In 1968 Nixon beat Humphry because of Vietnam. In 1992 Bush I almost beat the"draft-dodging" Clinton because of Vietnam (ironic because Bush I was supposed to have put the ghost of Vietnam to rest with our victory in the Gulf War). And now we have this. What? A fourth election turning into a referendum on Vietnam, 30 years after American participation in the war came to an end? Ah, but we lost. That's hard for the country to accept. Not even victory in the Cold War has succeeded in wiping away the stain.

Two, Bush is trying by his manipulation of this issue to turn the election into a referendum on Kerry's character rather than his own handling of the war on terrorism and the war in Iraq. Kerry loses if Bush succeeds in this attempt.

Three, a little historical context. Bush is not reinventing the wheel of politics. Attacking the war record of presidential candidates is an old and vibrant tradition in American politics. In some cases elections have turned on these attacks.

In 1960 Kennedy and Humphry were battling in the West Virginia primary for the Democratic nomination. JFK won in the end, perhaps, because he had had the wisdom to bring in Franklin Roosevelt, Jr. to reassure Protestant voters that Catholic Kennedy could be trusted with power. One of FDR Jr.'s most effective attacks was to smear Humphry as a draft dodger."There's another candidate in your primary," said Roosevelt,"but I don't know where he was in World War II." Bobby Kennedy apparently orchestrated the attacks. Asked to denounce them, Kennedy refused. (Humphry in fact had tried to get into the service, but failed because he could not pass the physical).

In the general election Kennedy ran as a war hero. This was ironic. Though he deserved praise for his courage in the aftermath of the attack on PT 109, it had apparently sunk because he had been inattentive as a commander, as Garry Wills long ago pointed out. JFK himself worried that the events could justify either a medal or a court martial. In the end he got the medal--after his father used his influence.

Kennedy as president tried to get his friend Ben Bradlee to do a story on Nelson Rockefeller's military record--or lack of one."Where was old Nels when you and I were dodging bullets in the Solomon Islands?" he asked one day.

I have drawn these examples of Kennedy's perfidy from It Didn't Start with Watergate, a book written by a rightwing journalist whose goal was to show that long before Nixon politicians played dirty.

Playing dirty--an American tradition. Unfortunately.