Des Moines, Iowa (CNN) -- Newt Gingrich's position at the top of the Republican presidential field made him the target of his rivals in the 12th major GOP debate Saturday in Iowa, a little more than three weeks before the state's caucuses launch the 2012 primaries. Here are five things we learned from the debate:
Attacking in a "relentlessly positive" way
For all his insistence on running a "relentlessly positive" campaign, Newt Gingrich did not back down when the other candidates went after him.
The lifelong historian would argue he isn't going negative but is simply contrasting his record against others'.
But it sure sounded like an attack when he said to Mitt Romney, "The only reason you didn't become a career politician is you lost to Teddy Kennedy in 1994. It's a bit much. You'd have been a 17-year career politician by now if you'd won."
Or when he chastised Michele Bachmann again for getting her facts wrong. And there were many more examples of what the Gingrich campaign is calling "contrasts."
"We are not going to go out of our way to attack our opponents, but we will respond with the facts if we are attacked. And Gov. Romney has been quite frequently going around accusing Newt of being a career politician, and we are not hiding the fact that he did serve in Congress," said Gingrich spokesman R.C. Hammond. "It's a difference between someone who's willing to put forward a political punch line in hopes that that raises up a campaign, versus someone who is actually going to go up there and solve problems."
Gingrich does get credit for keeping his cool while he fought back, and he managed to end the debate with a big grin.
Someone finally lands a blow on Romney
After 12 debates and countless public events, a non-Romney candidate finally landed some blows on the Teflon front-runner.
Romney has seemed almost untouchable throughout most of the campaign, but on Saturday he found a formidable opponent in Gingrich. Early on in the debate, Gingrich solidly hit Romney on the career politician claim, and once the first blow was landed, the other candidates piled on.
Some say that a muddled field is good for Romney -- that the rise of the other candidates helps divide the non-Romney vote. But as polls tighten in many of the early primary states, attacks on Romney are sure to increase, and if the attacks are as successful as they were at the debate, they might begin to have an effect.
Perry, Santorum fade into background
Neither Rick Santorum nor Rick Perry did much in this GOP matchup to change his standing.
Aside from a few notable moments, the two Ricks largely faded into the background in a high-profile contest that could have helped either build on low poll numbers in Iowa -- a state that both men hope could turn around their campaigns.
Perry did goad Romney into making a potentially damaging quip, when Romney disagreed with how Perry characterized something he'd written in his book.
Romney offered to bet Perry $10,000 he was right.
Democrats quickly said the line made Romney seem out-of-touch with struggling Americans, and Jon Huntsman -- who skipped the debate -- shot out a press release announcing he'd purchased the website 10kBet.com.
But at the end of the debate, the buzz centered on other candidates -- not what Perry or Santorum needs in the last few weeks before the Iowa caucuses.
Conservatives still searching?
No matter how much time candidates spend shaking voters' hands in Iowa, not one has been able to seal up the support of conservatives in the Hawkeye State. And revelations that bubbled up during this debate may help show why.
Romney acknowledged he grew up wealthy, and made his ill-advised bet with Perry. Plus he -- and Gingrich -- are still being dogged by past support for an individual health care mandate.
Santorum faulted Bachmann for a lack of legislative success -- but ignored the fact he lost his Senate seat in a rout. And Gingrich acknowledged his three marriages could provoke concerns in some voters.
"I've had to go to God for forgiveness," he said. "I think people have to measure who I am now, and whether I'm a person they can trust."
Look out for Ron Paul in the caucuses.
Gone but not forgotten
Although Herman Cain wasn't at the debate, Bachmann made sure that his memory lived on.
Bachmann brought up Cain's 9-9-9 plan three separate times and cited the former candidate's speaking style when asked to name something she'd learned from one of her challengers.
"I think one thing that he showed us is the power of being very plain-spoken," Bachmann said. "And also reducing something to a very simple level so people get it. And people were very excited about that plan, because they could understand what that meant. And I think that's a challenge for every one of us, 'cause a lot of times, you can end up sounding and talking like a big bureaucrat in Washington. People don't want that. They don't want Washington. They want outside of Washington. And rightfully so."
Cain polled at front-runner levels before his campaign was derailed by accusations of indiscretions, and Bachmann clearly sees his former supporters as an untapped resource. In the spin room after the debate, Bachmann campaign spokeswoman Alice Stewart said that the campaign would continue to make a push to win over undecided Cain supporters in the weeks before the caucuses. And while Cain has yet to come out and endorse any of his former rivals, Stewart said that the Bachmann campaign has been talking to his campaign.
"A lot of what she and Mr. Cain stood for were similar views, so it would be natural for the constituency to come support Michele," Stewart said. "A lot of what he said in terms of his plan and his visions -- it's useful. And she said from day one when he got out, he brought a lot to this campaign. He brought a lot to the debate, and the energy and enthusiasm he had is certainly something that would be wise of any campaign to try to tap into that."
CNN's Adam Aigner-Treworgy, Shawna Shepherd and Rachel Streitfeld contributed to this report.