How Gingrich's bitter ex-wife could shape tonight's debate

Updated with new poll results at 4:35 p.m.

The Republicans hold their last debate before the S.C. primary tonight, and breaking news this morning will directly shape it.

First up: There will be only four candidates on the stage in North Charleston. Texas Gov. Rick Perry dropped out of the race this morning and endorsed fellow anti-Romney candidate Newt Gingrich.

The big question, though, surrounds whether Gingrich will have to field questions about a new interview his ex-wife, Marianne, is doing with ABC News on Nightline tonight. She’s expected to say some nasty things about the man who admitted to cheating on her. But there are mixed signals coming out of the Gingrich campaign on how he’ll handle it. Some say he’ll fight back. Others say he’ll ignore it.

“It is pretty nasty to use personal tragedy for political exploitation,” senior Gingrich adviser Bob Walker tells the National Review. “That was a very bitter divorce, and you’re talking about somebody who is still, probably, very bitter.”

It will be interesting to see how Gingrich, needing to win a socially conservative state, handles it if questions about his infidelity come up. He said today he won't talk about Marianne. His two daughters, in a letter to ABC news, are defending him.

As for the Perry endorsement, we think it will give Gingrich a bounce. Perry was winning only 6 percent of the vote in Public Policy Polling’s most recent S.C. poll. But his impact could be greater than that because he’s dropping out so close to the primary and creating buzz. Gingrich was rising in the S.C. polls after Monday's debate anyway, so this will add to the momentum. A new Rasmussen poll has Gingrich trailing Romney only 30-27. But the Christian Science Monitor says that it’s not clear what’s going on with polls in the Palmetto State.

Update: Nate Silver of the New York Times summarizes six different S.C. polls that have all come out today. Three of those have Gingrich ahead slightly; two have Romney up by 7 and 10 points; and one has it as a virtual tie. Looking at the different polling methodology and other factors, Silver concludes there is "substantial momentum for Mr. Gingrich in South Carolina, giving him at least as strong a tailwind as Rick Santorum had in the closing days of the campaign in Iowa." Silver's model says South Carolina is now a toss-up.

One big question will be whether Marinanne's last-minute interview with ABC will slow Gingrich down.

CNN’s John King will moderate tonight’s debate. He tells the Boston Globe that “South Carolina gets their chest puffed out” for this primary.

South Carolina, and the Republican nomination, is still Romney’s to lose, despite Gingrich’s late surge. Pressure continues to build on Romney to release his tax returns, and you can be sure it will be an issue against Obama, especially if Romney doesn’t clear the air quickly. We at the Observer are less concerned about seeing his papers, we said in this morning’s paper, than we are about closing the “carried-interest” loophole that lets hedge fund managers and private equity executives have their fees taxed at 15 percent.

Taylor Batten