Tonight’s Des Moines debate had no meltdown moment for any candidate, although it did suggest Newt Gingrich is in for a tough time now that he’s not just an entertaining candidate, but a serious contender for the nomination. The debate followed Gingrich forced “clarification” of his comment remarking that Palestinians have an “invented” nationality.

His press secretary had lamely suggested earlier in the day: “Gingrich supports a negotiated peace agreement between Israel and the Palestinians, which will necessarily include agreement between Israel and the Palestinians over the borders of a Palestinian state. However, to understand what is being proposed and negotiated you have to understand decades of complex history - which is exactly what Gingrich was referencing during the recent interview with Jewish TV.” But of course he was not being complex or nuanced; he was being provocative and, if we are to believe he might be president, irresponsible.

The Des Moines debate suggested that Gingrich is still going to be his own worst enemy. He continued to insist on “truth” telling on the “made up” Palestinian assertion, only to be rapped by Romney for throwing “incendiary” words and playing the bomb throwing (figuratively) historian. In some ways it was a defining moment: Do you really want such a provocative figure in the Oval Office, as amusing as he may be?

Gingrich got himself lumped in with Mitt Romney (“Newt-Romney”) by Rep. Michele Bachmann (R-Minn.) on the individual mandate. He was tarred as a Washington insider by Bachmann, Rep. Ron Paul (R-Tex.) and Mitt Romney. He showed himself to be testy at times and lashed out at Romney for saying he’d have been a career politician if he hadn’t lost to Ted Kennedy in 1994. (The crowd booed strongly.) The conservative stalwarts Bachmann and Santorum made progress in painting him as inconsistent and not that conservative. Romney ribbed him for being in favor of giant mirrors in space and kids working as janitors. If his two-fold goal was to appear less risky as a potential nominee and show himself to be the only anti-Romney conservative he failed. And in one of the most painful interludes, a series of competitors said that infidelity was an issue. (Perry laid it on thick, saying that he took his own marital vow to God and his wife very seriously.)

Mitt Romney had one slip and will take some ribbing for it. When arguing with Texas Gov. Rick Perry about whether he had changed a line in his book (Romney was right on the facts) he offered Perry a $10,000 bet. Ouch. Yeah, he’s rich. But he also had an excellent debate. For one thing, he finally talked about his work for the Mormon church, both in counseling troubled people and in working on a mission in France. It was humanizing, and you wonder if he should have opened up more in this regard, earlier in the race.

Romney gave his best defense of RomneyCare, pointing out that ObamaCare by contrast raised taxes and cut Medicare. He cited the 10th Amendment back to Perry, stressing that states should be able to do what they wanted on healthcare reform. He was impressive on the Middle East, making the forceful case that he will be stable and sober, while Gingrich will inflame already explosive situations. He stressed again and again his private sector background, which is a unique asset in the field now that Herman Cain is gone. And most of all, he highlighted the contrast in demeanor. He was good-humored, calm and firm. If he can now make this a contrast campaign with the often snippy Gingrich on issues of temperament and stability, he’ll be in good shape.

The three candidates in the back of the pack all had excellent performances. Perry gave an extremely strong answer on national security, chiding President Obama for letting Iran get one of our drones. He poked at both Gingrich and Romney on the individual mandate. On illegal immigration, instead of attacking Romney over his gardening help, Perry made an excellent point: Through good enforcement the number of illegal immigrants goes down and the problem of legalizing or returning them home becomes easier.

Rick Santorum had his best debate of the election cycle. He was more at ease, gentle in tweaking his opponents and solid on reiterating his background as a consistent conservative on Iran and healthcare. In talking about his humble beginnings he went to his strong suit — emphasizing the importance of an in tact family. And in speaking on the infidelity issue he was impressively restrained, pointing out the role of redemption.

Bachmann also had her strongest debate night to date. She came up with the Newt-Romney formulation, which is a deadly one for Gingrich. She made her points on ObamaCare and Gingrich’s work for Freddie Mac (chiding him for having an office on K Street, “the Rodeo Drive of Washington”), using humor and conveying an earnestness that has sometimes not been shown. She also made a pitch for the Cain voters, citing 9-9-9 and paying tribute to his boldness.

And finally, Ron Paul is going to keep his devoted fans, making an appeal on spending and his fidelity to the Constitution (“Sometimes I was the only one voting no!”). He did a brief rant on staying out of the Middle East, but was otherwise without any of his tell-tale wacky moment. (His explanation of the Fed induced bubble was as sober a description of the financial meltdown as he has delivered.)

Winners: Bachmann, Santorum, Perry — and because they can take steam out of Gingrich and he demonstrated a superior temperament, Romney too was a winner

Losers: Gingrich (who did himself no good and some harm) and Diane Sawyer (who sounded as if she were addressing a kindergarten class).