Gingrich has said he should have responded to Restore Our Future's ads sooner. That's the same lesson Dukakis, the 1988 Democratic nominee, took away after he was targeted by a McCarthy-made ad.

"The worst decision I ever made" in the campaign was not responding to attacks including the Willie Horton ad, which was aired by a committee independently promoting George H.W. Bush's campaign, Dukakis said in an interview.

"As in the case of the Swift Boat ad, I don't think we took it very seriously," Dukakis said. "It was, after all, a so-called independent group."

"You cannot remain mute, which is what I did," he added.

Death Bed Regrets

The Bush campaign also linked Dukakis to Horton. Lee Atwater, the Republican operative who helped Bush defeat Dukakis, said before he died of cancer in 1991 that he regretted the attacks, which were widely condemned as being unfair to Dukakis and racist in tone.

Eight years ago, the anti-Kerry Swift Boat ads generated enough controversy that "swiftboat" entered the political vernacular as a verb for airing hard-hitting ads. Those ads accused the Kerry, a Massachusetts senator who was awarded a Bronze Star, a Silver Star and three Purple Hearts while serving in Vietnam, of exaggerating his war record.

"I'd like to see us get to a better place in politics where the word Swiftboating is retired from the political vocabulary," Kerry said in 2010.

Senator John McCain of Arizona, the Republican Party's 2008 presidential nominee and a Vietnam veteran, told MSNBC in August 2004 that the commercials were "dishonest and dishonorable."

Destructive Ads

Tad Devine, a Kerry campaign strategist, said in an interview that "there's a perception on the Republican side that the Swift Boat advertising was very destructive for John Kerry, so I think naturally they would want to hire a firm that would make those kinds of ads."

Brittany Gross, a spokeswoman for Restore Our Future, declined to comment on PAC's vendors or strategy.