Is Newt Gingrich only hurting himself with attacks on Mitt Romney?

The Newt Gingrich assault on Mitt Romney’s business credentials will get a lot more exposure in South Carolina. But in politics even effective negative ads can rebound and hurt the attacker.

Newt Gingrich does not appear to be backing down from his attacks on Mitt Romney’s record at Bain Capital. In an interview with Fox News’s Greta Van Susteren on Thursday the ex-speaker doubled down on his assertions that Mr. Romney had broken companies and thrown people out of work, saying that he was talking about the actions of one individual as opposed to all of free enterprise in general.

“This isn’t about capitalism. This isn’t even about private equity funds. This is about one person who wants to be president of the United States,” said Mr. Gingrich. “He owes the country an explanation. Why were certain decisions made? How were they done? What was the consequence of them? Does he stand by them in retrospect?”

This assault on Romney’s business credentials will get a lot more exposure in South Carolina – the next state to hold a GOP primary – beginning today. The pro-Gingrich super PAC Winning Our Future on Thursday plans to start airing ads based on a 27-minute “King of Bain” video that includes interviews with workers who claim they lost their homes and livelihoods due to Bain actions.

There’s some evidence that Gingrich’s aggression is working. A new InsiderAdvantage poll of likely GOP voters in South Carolina has him at 21 percent, with Romney at 23 percent – a statistical tie.

But other polls still have Romney with a comfortable lead in the Palmetto State. He appears to be way ahead in Florida, next up on the primary schedule. Some hold-out conservatives are beginning to rally around Romney in the face of anti-Bain attacks from Gingrich and Rick Perry.

Is Gingrich thus only hurting himself with his decision to resort to campaign trench warfare?

For one thing, it’s a truism in politics that even effective negative ads can rebound and hurt the attacker as well as the attackee. And Gingrich has made it very clear that he approves of the anti-Bain ads, even though they’re funded by a Super PAC over which he has no control, technically-speaking.

It may already be happening. In New Hampshire, a plurality of 27 percent of voters said that Gingrich ran the most negative campaign in the state. Yet, as Slate’s Dave Weigel pointed out yesterday, Gingrich in fact did not run any negative ads in New Hampshire.

“Voters were reacting to the Bain talk,” wrote Mr. Weigel on Wednesday.

Plus, Gingrich is opening himself up to retaliation. The Super PAC associated with Romney, Restore Our Future, is well-funded and has already shown that it has no compunctions about going after Romney’s GOP opponents. It’s already airing an ad in South Carolina titled “Desperate” that quotes conservatives saying Gingrich’s anti-Bain attacks are “disgusting,” and so forth, and reminds viewers once again of Gingrich’s own political liabilities, such as his multiple extramarital affairs.

“Newt attacks because he has more baggage than the airlines,” says the ad’s narrator.

Finally Newt may be doing harm to Gingrich, Inc. Many in the GOP are upset at his actions, saying that he’s carrying water for Democrats. The Bain ads are surely a preview of what the Obama campaign would produce in a general election contest with Romney, they point out. In that sense Gingrich may be only softening up the party’s probable nominee for November.

Imagine how Gingrich’s many Washington-based business ventures might fare if Romney is the nominee, but loses. He might be shunned by former allies. Or what if Romney wins? Under a Romney administration, Gingrich-linked firms could become companies non grata.

In his Fix blog today Washington Post political analyst Chris Cillizza quotes a senior GOP figure thusly: “If [Gingrich] persists in trying to launch Newt nukes, then there will be those who react firmly in cutting off diplomatic relations and impose sanctions: invitations not extended, speaking opportunities cut off, certain TV opportunities don’t appear, help in clearing up campaign debt isn’t offered,” said the anonymous Republican.