(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.