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."