What a strange, out-of-sync country is America. Here we are fighting a real war in Iraq and our presidential campaign has been bogged down in a nasty debate about what did or didn't happen on a river patrol boat 35 years ago in Vietnam.

President Bush was wise to praise John Kerry's war record yesterday, perhaps breaking the Vietnam feedback loop of ill will that had been evident in a series of anti-Kerry advertisements. "The old wounds have been reopened, and they still bleed," Larry Thurlow, an organizer of Swift Boat Veterans for Truth, the group that has been running the TV ads attacking Kerry's war record, said recently. Thurlow, to be sure, has been doing his best to pick at the scabs.

The attacks on John Kerry's military service in Vietnam were politically risky, coming from supporters of a Republican candidate who didn't serve in that war. But it must be said that Kerry invited this sort of scrutiny by making his Vietnam exploits the centerpiece of last month's Democratic convention.

When Kerry assembled his Swift boat "band of brothers" on the convention podium, and when he opened his acceptance speech with the silly "reporting for duty" line, he set up the Republican counterattack. Once Kerry had made his Vietnam service the measure of his character, it was inevitable that Bush supporters would try to challenge that record.

So Thurlow and his Swift Boat Veterans for Truth went on the attack. The measure of their success is that by the end of last week, their advertising barrage had knocked Kerry off his bland, above-the fray strategy. The genial Mister Roberts of the convention started firing back. And the news media began examining in detail the competing accounts of what happened on the Bay Hap River in 1969.

The attacks on Kerry were risky for several reasons. First, many of the critics are now caught in contradictions between what they say in the ads and previous statements and military records. The commander of Kerry's Swift boat task force, Roy Hoffmann, for example, says in the ad that "Kerry has not been honest" in his claims of valor. But on the day in 1969 when Kerry won his Silver Star for counterattacking a Viet Cong ambush, Hoffmann sent a radio message praising the tactic as "a shining example of completely overwhelming the enemy." Similarly, Thurlow's charge that Kerry wasn't under enemy fire when he won his Bronze Star is undermined by the Bronze Star citation Thurlow himself received for his actions that day, which speaks of "enemy small arms" and "automatic weapons fire."

The most powerful rebuttal of the anti-Kerry charges comes from William B. Rood, the commander of another of the Swift boats on the river the day Kerry won his Silver Star. "I know that what some people are saying now is wrong," Rood wrote Sunday in the Chicago Tribune, where he works as an editor. "While they mean to hurt Kerry, what they're saying impugns others who are not in the public eye."

A second danger for the Bush campaign was that the Swift Boat Veterans' attack ads exposed Bush's character to greater scrutiny. The public has been forgiving of a rich man's son who avoided Vietnam service, failed in many of his early business ventures and had an early history of alcohol abuse. Bush has gotten a pass partly because he's seen as a likable, decent fellow. That's a precious commodity for the Bush campaign, and it could be put at risk if character flaws of 30 years ago become the issue.

The biggest problem for Bush supporters in condoning the attacks against Kerry was that they may anger the public. Republicans have taken negative advertising to remarkable lengths, questioning the patriotism of legless Vietnam veteran Max Cleland in a 2002 Senate race and the conservative credentials of ex-POW Sen. John McCain in the 2000 Republican primaries.

Attacks of this sort may work for a time, but they risk destroying the attacker. A famous example is the way Sen. Joe McCarthy's red-baiting crusade self-destructed after he began hunting for supposed subversives in the U.S. Army. The army's counsel, Joseph N. Welch, responded unforgettably: "Have you no sense of decency, sir, at long last? Have you left no sense of decency?" That marked the beginning of the end for McCarthy.

Bush still hasn't condemned the ads explicitly, but he should. Even Karl Rove should realize that condoning ads attacking a wounded war hero's patriotism is a dangerous business. At some point, the public may ask: Have you no sense of decency, sir?