(Bloomberg News) A group supporting Mitt Romney has spent millions attacking Republican rivals Rick Santorum and Newt Gingrich -- using media firms better known for ambushing Democratic presidential nominees Michael Dukakis and John Kerry.

The ads for the political action committee, Restore Our Future, are created by McCarthy Hennings Media Inc., whose president, Larry McCarthy, produced an ad during the 1988 presidential campaign linking Dukakis, then governor of Massachusetts, to Willie Horton, a black parolee from that state who committed armed robbery and rape while on a prison furlough. The ad, which featured a menacing mug shot of Horton, helped Republican George H.W. Bush win the White House by portraying Dukakis as soft on crime.

Restore Our Future is placing its ads on television through the Towson, Maryland-based firm Mentzer Media, which received more than $18 million from Swift Boat Vets and POWs for Truth to place ads that questioned the Vietnam War record of Kerry, who was awarded five medals including the Silver Star for his service.

The strategy of Restore Our Future has been "focused on tearing down the opposition," Bill Allison, editorial director at the Sunlight Foundation, a Washington-based advocacy group, said in an interview.

"It's almost like a scorched-earth policy, where they're really trying to look for the weakness of a candidate and exploit it as much as possible," Allison said.

Bare-Knuckles Fight

The background of Restore Our Future's vendors underscores the bare-knuckles role of independent political committees known as super-PACs, which can raise unlimited funds from any source to air ads that attack opponents.

All 12 ads that Restore Our Future has spent about $12 million airing on broadcast television as of Feb. 13 in the Republican presidential race have been negative in tone, according to New York-based Kantar Media's CMAG, which tracks advertising.

The PAC's latest ad attacks Santorum, a former U.S. senator from Pennsylvania who is now Romney's chief rival for the nomination, for votes to raise the federal debt ceiling and for a transportation bill that included some parochial spending projects known as earmarks. "Rick Santorum: Big spender, Washington insider," the ad concludes.

Although the commercial singles out Santorum's votes, most Republicans in Congress at the time, including Minority Leader Mitch McConnell of Kentucky, voted the same way as he did on those issues.

Pre-Emptive Attack

To defend himself, Santorum's campaign has released on its Web site an ad targeting Romney and Restore Our Future. It shows a Romney impersonator trying to shoot balls of mud at a cutout of a smiling Santorum.

"Mitt Romney's negative attack machine is back, on full throttle. This time Romney's firing his mud at Rick Santorum," a narrator says.

As of yesterday, the ad hadn't appeared on broadcast television, according to CMAG.

The negative advertising may be taking a toll on Republican candidates including Romney, Jack Pitney, a political scientist at Claremont McKenna College in Claremont, California, said in an interview.

Romney's unfavorable rating was 49 percent in a Feb. 8-12 survey by the Pew Center for People and the Press, up from 42 percent in a Jan. 11-16 survey. Gingrich's unfavorable rating in the February poll was 57 percent, up from 48 percent in November. Santorum was not part of the Pew Center's November survey; in February, his unfavorable rating was 36 percent while 33 percent viewed him favorably.

General Election Shield

While the negative ads are doing some damage, Pitney said, it's possible they might serve as a "form of inoculation" for the eventual Republican nominee before the general election, when attacks may have less effect if Obama and his allies reprise them.

"It's kind of like a live-virus vaccine," Pitney said. "You don't know if it's going to provide protection or create the illness it's trying to prevent."

Restore Our Future is shifting its attention away from Gingrich, who has slipped in polls and become hobbled by tight finances since he won the Jan. 21 South Carolina primary. Gingrich has denounced the PAC's ads, saying on Feb. 4 that Romney and the ads were "fundamentally dishonest."

'Pants On Fire'

PolitiFact, a nonpartisan site that truth squads political discourse, issued a "pants on fire" rating today to a Restore Our Future ad that said Gingrich backed a bill supporting China's one-child policy limiting population growth. PolitiFact said the bill, which authorized money for a United Nations program, barred the use of funds for "involuntary sterilization or abortion or to coerce any person to accept family planning."

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.

The emergence of super-PACs is a financial windfall for political professionals, including the media firms that Restore Our Future employs. It has paid more than $15.3 million to Mentzer Media to reserve television time to air ads. Most of the money goes to the stations, while Mentzer Media keeps a percentage that it and the campaign don't disclose.

McCarthy's company received more than $284,000 to create ads for the pro-Romney PAC. McCarthy is one of three members of Restore Our Future's board and worked on Romney's losing 2008 presidential campaign.

Wanted In Foxhole

While McCarthy has drawn criticism for his tough tactics, Republican political strategist Ed Rollins, in a 1996 book, included McCarthy on a list of "Guys I Want in the Foxhole with Me if I'm Ever Stupid Enough to Run Another Presidential Campaign."

Red, White and Blue Fund, the main super-PAC helping Santorum, also has ties to the Swift Boat campaign. It has given more than $1.6 million to Alexandria, Virginia-based SRCP Media Inc., to produce and air ads. The group created ads for the Swift Boat group in 2004.

"The monies being raised and spent by the super-PACs offer a new revenue stream for media consultants and media buyers," Anthony Corrado, a political scientist at Colby College in Waterville, Maine, said in an interview.