Mitt Romney needed a strong debate on Monday night. And he needed Newt Gingrich to be unimpressive. He went two for two.

Romney started strong, bashing at Gingrich’s time at Freddie Mac, hitting him for influence peddling on Medicare Part D and chiding him for getting thrown out as speaker. His own defense of his success in business was more energetic than it has been, and he declined the chance to pander to audiences on sugar subsidies and on bilingual ballots ( he’s against both). He gave a tough answer on the Straits of Hormuz, declaring that Iran’s effort to close it would be an act of war. When asked how we could win in Afghanistan without negotiating with the Taliban, he said incredulously, “By beating them?” He was barely asked about RomneyCare and escaped by defending states’ right to pass their own plans. When pressed on what he did to advance conservatism he said he had a family (outpopulate the liberals?), worked in the private sector and ran Massachusetts as a conservative.

On his own tax returns he rebuffed a weird question asking him what people would find surprising in his tax returns. (Huh?) And he cleverly pointed out that under Gingrich’s tax plan Romney would have paid nothing on capital gains.

Romney is too well-mannered to raise his voice or interrupt. But he nevertheless dominated the debate in a way he had not previously. While he attacked in a low-key manner, the substance of his attacks essentially went unrebutted.

Gingrich, by contrast, seemed sleepy and unwilling to engage. With the audience ordered to be quiet and without feisty questions from Brian Williams, he seemed listless. On Freddie Mac he didn’t have a credible explanation for why his contract called for him to report to the head lobbyist for Freddie, pleading instead that he was just a “consultant.”

On his speakership, he tried to argue that he voluntarily stepped down. Rep. Ron Paul (R-Tex.) called him on it, saying he left because he didn’t have the votes to be re-elected speaker. Gingrich in turn tried to characterize this line of questioning as unduly personal or nasty. But of course his record is entirely relevant to his campaign.

His best answer came toward the end when he defended his conservative credentials going all the way back to Barry Goldwater. But if he is counting on the debates to equalize the playing field (with the much better-funded Romney), Gingrich will need a livelier performance on Thursday.

Rick Santorum gave solid answers on Cuba and Iran. But when asked to make the case for his own electability, he lacked a punchy answer. He did not have the opportunity to do what he does best — weave social and economic policy together. In the back-and-forth between Romney and Gingrich, he seemed to be a bystander. He came alive later in the debate, hitting both his opponents on the individual mandate, cap-and-trade and TARP, arguing there is no difference between the two frontrunners and the president. It may have been his best answer in any debate. If he does more of that in the next debate, he can help himself stay in the fight.

Finally, Ron Paul was a bit player in the debate. His most memorable contribution was in sticking it to Gingrich on the loss of support from House Republicans. He, as he has before, decried starting a “hot war” in Iran and called for slashing the military

Winner: Mitt Romney

Losers: Newt Gingrich, Brian Williams (for a excess of process questions and weirdly trying to get Romney to indict himself on his tax returns)