The guys trailing Mitt Romney were expected to finally unleash their harshest attacks on him last night, and they didn't. Now that they've slept on it a few hours, maybe the Not Romneys will figure out this is their last chance to make the case for their candidacy before the New Hampshire primary on Tuesday. Or maybe they'll be too sleepy to be mean on a Sunday morning. We're liveblogging the second debate in the last 12 hours -- and the fifteenth in the last right months -- which airs on NBC at 9a.m. eastern time.

Updates:

11:00a.m.: The Not Romneys attacked Romney a bit, though they were distracted by Paul's "sermon on liberty" this Sunday morning. A new poll shows Romney is still far ahead of his rivals, but his support is slipping a bit. Huntsman, who has campaigned only in New Hampshire, is gaining a little. But how is the guy going to win over voters if he never smiles?

Despite the importance of the supposedly fiscally-focused Tea Party in the past few years, debate moderators have taken a lot of time to talk about gay people. It's probably because it's fun to watch the candidates squirm. Even Santorum -- famous for comparing homosexuality to "man on dog" -- talked about how everyone should be treated with "dignity" regardless of sexual orientation. It's interesting to watch a wedge issue start to wedge the other way. While Romney is getting better at talking about his past moderation on social issues, his body language shows he still would much rather prefer talking about managing the economy. 

In a lighter moment, Gingrich was really proud of Perry for naming all three government agencies he wanted to get rid of:

(Photo via Reuters.)

10:41a.m.: A woman in the front row behind moderator David Gregory spent part of the debate napping. Video of her asleep:

10:37a.m.: Agence France Presse's Olivier Knox tweets, "Gingrich tells Callista he aced his 'Pawlenty moment' as #nbcfbdebate microphones stay on during break."

10:20a.m.: Romney vs. Gingrich is entertaining bit of acting. Supposedly they are debating the negative ads against each other, but it's just a chance to make the attacks against their opponent made by the officially independent political action committees. They both pretend to think the other's attacks are so silly they can't help but smile:

Buzzfeed's McKay Coppins tweets, "Newt seems very familiar with this anti-Romney video he hasn't seen. Romney also pretty well-versed in anti-Newt ads he hasn't seen."

10:16a.m.: Republican strategist Mike Murphy tweets, "What happens during commercials. Candidates wander, audience stands and chats."

10:13a.m.: Here's an opportunity for a question we haven't heard at the previous 14 debates. Perry says, "We have a president who is socialist." But this week, Romney called Obama a "crony capitalist." Well! Which is it guys -- is Obama a socialist or a capitalist?

10:09a.m.:  The Suffolk University/7News overnight tracking poll was just released -- it finds Romney and Santorum slipping. Romney has fallen four nights in a row, the press release says, and is down to 35 percent. That's a drop of 8 percentage points since Tuesday. Behind Romney is Paul with 20 percent, Huntsman with 11 percent, Gingrich with 9 percent, and Santorum with 8 percent. The poll finds 15 percent undecided.

Paul leads Romney among young folks by 39 percent to 25 percent. Huntsman is doing better among young independents, going from 10 percent to 18 percent. And he's second to Romney among independent seniors.

10:03a.m.: Sometimes, when you're, say, writing about the fifteenth Republican debate, you wonder if any regular people actually care about this stuff. And then you see your favorite gymnastics blogger tweeting about the right to privacy. It's cheering.

9:57a.m.: When Romney's talking about the economy, he talks with enthusiasm -- and with his hands. When he's talking about social issues, they drop to his side. On how government overhead in social programs means that not that much aid goes to the people whom those programs are supposed to help:

On gay marriage:

Still, he's gotten better at answering the gay marriage question. "When was the last time you spoke up for increasing gay rights?" the moderator asks. "Right now," Romney says, to audience approval.

9:41a.m.Huntsman says he wants to generate excitement and enthusiasm. But that's going to be really hard, since he hasn't been able to do that much in the debates. Huntsman never looks happy in these debates -- he looks like he's lecturing a surly teenager. 

Look at that last image! It looks like frustration bordering on disgust. Though Huntsman opened his campaign promising to bring civility to the debate, he hasn't made up for the lack of negative energy against Obama and his rivals with positive energy about his own ideas.

9:37a.m.: Santorum says Paul hasn't been able to pass anything. People love him because of his economic plan, but "he's been out on the margins." What Paul could do as president, Santorum says, is have an impact on foreign policy -- and that would be a very bad thing.

It's not exactly a simple task to reverse 100 years of sliding away from our constitution, Paul responds.

Talking Points Memo's Benjy Sarlin points out that once again, Paul has shifted the conversation away from Romney.

9:34a.m.: Ron Paul says the reason he hasn't gotten much legislation passed as just proof how "out of touch" Washington is with the American people. That doesn't really make a good case for his ability to change the country as president.

9:32a.m.: Gingrich is most charming -- even when he's smirking -- when he's talking about his glory days as House speaker. When asked about Senate Majority Leader Harry Reid's statement that he'd try to make Gingrich a one-term president, Gingrich smiles and says, "every president who wants to work with the opposition knows they want to make him a one-term president." He says he got a lot of things done with Bill Clinton even though Clinton knew Gingrich wanted him to be a one-term president. 

9:28a.m.: Romney had a great debate last night because he knew he was winning. When he's challenged -- in aggressive interviews, in the debate in which he grabbed Perry on the shoulder -- he gets irritated and says weird little "ha ha"s. So far he's kept his cool. But you can imagine a few "ha ha"s over breakfast this morning while reading an op-ed by the New Hampshire Union Leader's Joseph McQuaid, saying that while conventional wisdom holds that Romney has the "best chance" to beat President Obama, "on the contrary, Romney may be the worst candidate."

9:23a.m.: Perry is sounding a lot better than he has in previous debates. There are fewer mid-sentence pauses that make everyone cringe that we're about to have another "oops" moment.

9:21a.m.: On entitlements, Huntsman says he'd introduce means-testing -- rich folks don't need Medicare. Gingrich attacks the media in his response backing an entitlement overhaul. Perry says people aren't "clamoring for government assistance." 

9:16a.m.: Huntsman finally defends himself, and the crowd likes it. Romney "criticized me while he was out raising money for serving my country -- yes under a Democrat," he says.

I think we serve our country first by working for conservative principles, Romney says.

It's ideas like that that are dividing our country, Huntsman responds, to cheers.

9:11a.m.: Romney proudly notes that when he ran for Senate against Ted Kennedy in 1994, Kennedy was forced to take a mortgage out on his house. It is a weird way to say you made it a tougher election than Kennedy expected.

9:10a.m.: Wow, well Gingrich, who had said he was ready to fight last night but didn't, is attacking Romney as a professional candidate who lost to John McCain of all people. 

9:05a.m.: Jon Huntsman's campaign has suffered from a lack of money -- ironic, given his family is one of the richest in America, The New York Times' Jim Rutenberg reports. Huntsman reportedly doesn't want his dad to buy the election for him. Rutenberg writes:

In a strategy memo for supporters, Mr. Weaver noted that Mr. Huntsman had moved from ninth place months ago to a tie for third in several recent polls. He laid out a possible situation in which Mr. Huntsman exceeds expectations here on Tuesday and then goes on to South Carolina and Florida with enough momentum to eventually emerge as the sole rival to Mr. Romney in the race.

Expectations are really low. But even if he comes in second or third, conservative voters are looking for a conservative alternative to Romney, right? Why would they suddenly jump behind a moderate like Huntsman, who has gotten the most attention during this campaign by making fun of Republicans on Twitter?