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Newt Gingrich faces his first debate as the front-runner for the Republican presidential nomination, putting pressure on his main rival, Mitt Romney, to go on the attack with less than a month to go before the leadoff Iowa caucuses.

The Saturday night debate will focus on the federal budget deficit. It also promises a political drama as Gingrich and Romney meet amid a sharp back-and-forth waged by their campaigns.

Romney's campaign has launched an all-out offensive against Gingrich's record and leadership, particularly during his tenure in the 1990s as speaker of the House of Representatives. Gingrich has countered by questioning Romney's conservative credentials, pointing to his past support for abortion and gay rights as the governor of Democratic-leaning Massachusetts.

Gingrich rose to the top of polls largely because of how he's performed in the other 10 debates this year. This debate is the first since businessman Herman Cain dropped out of the race amid allegations of sexual harassment and an extramarital affair. Polls show that Gingrich has benefited the most from Cain's withdrawal even though he has been married three times and acknowledged his own extramarital affairs.

Gingrich's campaign was all but written off earlier this year when most of his top staffers abandoned him and he reported that his campaign was nearly $1 million in debt. Gingrich is expecting his new position in the race to mean his rivals will criticize him directly this time, aides say.

If they do, aides say Gingrich knows how he hopes to handle it: Pause, step back and laugh.

That's how Gingrich has responded in the past to what he's often deemed "gotcha" questions from debate moderators -- before dressing them down, usually to much applause from the audience.

"I wish you would put aside the gotcha questions," Gingrich snapped at Fox News anchor Chris Wallace during one debate. In another debate, the former House speaker told Politico editor John Harris, "I'm frankly not interested in your effort to get Republicans fighting each other."

His challenge Saturday night will be maintaining that cool and passing the temperament test in the face of the kind of repeated, sustained attacks that he's avoided in previous sparring matches when he lagged below the top tier of candidates in polls of likely Republican primary voters.

Responding the wrong way could reinforce charges from some within the party establishment that he's too undisciplined to lead the country.

The criticism could come from any corner. As the days dwindle before voting begins Jan. 3 in Iowa, almost all of his rivals are piling on in an effort to blunt Gingrich's momentum and raise their profile in Iowa. Minnesota Rep. Michele Bachmann has called Gingrich an "influence peddler." Former Pennsylvania Sen. Rick Santorum has criticized Gingrich's record in Congress, and Texas Gov. Rick Perry has hit his support for a national health insurance mandate in the 1990s.

Most likely to take a swipe at the front-runner are Texas Rep. Ron Paul and Romney, who are next in line in Iowa polls. Paul is running an ad accusing Gingrich of "serial hypocrisy." Romney's campaign has used Gingrich's critical comments about Rep. Paul Ryan's plan to overhaul the Medicare health insurance program for the elderly -- Gingrich once called it "right-wing social engineering" -- to accuse him of irrational decision-making and poor leadership.

Romney has been content to let surrogates and others backing his campaign provide the sharpest words against Gingrich. On Friday, in remarks to The Des Moines Register's editorial board, he spoke more directly about policy differences with Gingrich and how their experiences separated them.

Romney spokeswoman Gail Gitcho said the former Massachusetts governor won't step back from criticizing Gingrich's record during Saturday's debate. "He's going to draw a contrast between his record and the other candidates. I think you've seen the beginning of that this week," she said.

Romney's strategy with Gingrich is beginning to mirror what his campaign did with Perry, who entered the race in August and immediately rose to the top of polls. Ahead of debates, Romney's team rolled out new attacks on Perry -- first hitting some of the Texas governor's comments likening Social Security to a fraudulent "Ponzi scheme" and then attacking him for his more moderate record on immigration. Romney also delivered those attacks himself in two debates.

Romney has turned in a series of strong debate performances himself. He's made few mistakes and hasn't been repeatedly attacked by his rivals. Romney has emphasized his extensive experience as a businessman, contrasting that with Gingrich's background as a Washington insider.

"I think I've got the best ideas for our nation," Romney said at a campaign stop Friday. "I think I've got some pretty good zingers. I think I will be able to best post up against the president, particularly if we're talking about the economy."

But it's Gingrich's performances that voters have noticed. In a Des Moines Register poll released in early December, 50 percent of likely caucus-goers said Gingrich is the best debater. Romney was a distant second with 14 percent.

Aides say his success is due, in part, to careful study.

Since May, Gingrich has been practicing speaking in one-minute intervals, the length of time required by the debates. He's done it both in debate preparation -- originally with the help of campaign staffers who abandoned him in June -- and on the campaign trail, giving prepared speeches in one-minute pieces.

He's specifically prepared by reading through almost all of Ronald Reagan's debate transcripts from his 1980 presidential campaign, looking to learn from Reagan's communication style.

Reagan's most salient lesson for Gingrich heading into Saturday night's debate comes from his famous exchange with President Jimmy Carter.

As Carter launched into an attack on Reagan's views, Reagan defused it with four words that came to define the campaign: "There you go again!"