New York ? President Bush and Sen. John Kerry gave in to the wishes of popular maverick John McCain on Thursday, as the president embraced the Republican senator’s legal fight against big-money special interest groups airing negative ads and the Democratic nominee scrapped a commercial that featured McCain.

Their bitter fight over Vietnam-era military service took a compelling new twist as Kerry stood by the central charge in his ad: that Bush has used smear tactics to undercut the Democrat’s valorous combat record. “I am absolutely telling you the God’s honest truth about what happened and what took place over there,” Kerry told supporters in Minnesota.

He has been on the defensive since a group financed by Bush supporters, Swift Boat Veterans for Truth, aired a television commercial early this month accusing Kerry of exaggerating his wartime experience. Calling the group a front for the Bush campaign, Kerry unveiled an ad this week that features four-year-old footage of McCain accusing Bush of smear tactics in their bitterly contested 2000 GOP primary race.

The fierce response reflects concerns inside the Kerry camp that the debate could undercut his signature political theme: As a decorated Vietnam veteran, Kerry argues, he is capable of replacing the incumbent Republican while the nation is at war. It is too early to tell by polls whether the debate has hurt Kerry. Or whether it has exposed Bush, who served stateside in the Texas Air National Guard during the war, to voter backlash.

The only obvious winner is McCain, a former Vietnam War hero who emerged from his 2000 defeat as one of the nation’s most popular politicians, beloved by independent voters and courted by both presidential candidates. He has welcomed the attention, often instigating it, with an eye toward a possible run for the presidency in 2008.

Three weeks ago, the Arizona senator asked Bush to condemn the anti-Kerry ad. This week, he asked Kerry to withdraw the anti-Bush ad.

With their actions Thursday, Bush and Kerry satisfied McCain’s demands.

Announcing that Kerry had yanked his ad, spokesman David Wade said, “It’s long past time that Bush also take McCain’s advice and do the right thing by putting an end to the smears and lies on John Kerry’s service.”

Bush has criticized all outside group attack ads, including the Swift Boat Veterans group’s first commercial, but has not denounced the ad specifically. Kerry’s campaign insisted that by failing to condemn the group’s claims, the Republican was tacitly embracing them.

McCain sought to take Bush off the hook, suggesting that the president had gone far enough in condemning the accusations.

Attacking 527s

The political reprieve came only after the White House announced that Bush will join forces with McCain in legal action to crack down on political ads aired by outside groups, dubbed “527s” because of the section of the tax code that covers them.

“The president said if the court action doesn’t work, that he would be willing to pursue legislative action with Sen. McCain on that,” White House spokesman Scott McClellan said after Bush called McCain with the news.

McClellan did not indicate how quickly Bush would act. Election Day is Nov. 2.

McCain, an advocate of campaign finance reform, welcomed the White House embrace and said he would soon press forward with efforts to force Democratic and Republican groups to live within fund-raising limits. Currently, the 527s raise money with few limits under so-called “soft money” rules.

McCain suggested, and associates privately confirmed, that he had accepted Bush’s statements as proper condemnations of the anti-Kerry ad.

“I’ve said before I would like for the president to specifically condemn that ad, but the president has said John Kerry served honorably and also the president is now committed to acting to try to bring 527s into regulation,” McCain told The Associated Press. He said the lawsuit will likely have no impact on the election.

‘A little ironic’

Kerry’s advisers belittled the White House action, calling it a ploy to gloss over the attacks against their boss.

“It’s a little ironic that George Bush is now trying to assume the mantle of campaign finance reformer given the fact that he worked so hard to block the McCain-Feingold bill when it came up for a vote,” Kerry spokesman Phil Singer said, referring to campaign finance legislation sponsored by McCain and Democratic Sen. Russell Feingold of Wisconsin.

Kerry running mate John Edwards took a glancing jab at Bush while campaigning in New Mexico, denouncing “the same old false, negative attacks.”

In Minnesota, Kerry pointed out that the Navy documented his actions 35 years ago, and called the accusations “the lie that’s been put out there.”

While many Democrats want the controversy to go away, Kerry’s team plans to keep it alive at least until Bush’s convention gets under way here next week. His team is underscoring ties between the anti-Kerry group and the Bush campaign. Republicans say there are similar ties between Kerry’s campaign and Democrats 527s.

Neither side has proved that the other illegally coordinated with the outside groups.

A Los Angeles Times Poll shows Kerry losing a bit of ground since July on questions related to his Vietnam experience, his honesty and his fitness to serve as commander in chief. A CNN-USA Today survey shows that people believe 2-to-1 that Kerry is probably telling the truth about his Vietnam record.

But Kerry lost half the support of people who said they would vote for him based on what they learned about his military experience during his convention last month.