(CNN) -- Six candidates will be on the stage Saturday night at the Republican presidential debate in Iowa, but one of them may have the most on the line.
With time running out -- there are just more than three weeks until the Iowa caucuses -- all of the candidates need a strong showing, but Newt Gingrich has the most at stake.
A lot has changed for the former House speaker since the last GOP debate, a CNN showdown in Washington just before Thanksgiving. Since then, Gingrich's numbers have soared. He's the front-runner in latest national polling and in new CNN/Time ORC International surveys in Iowa, South Carolina and Florida, three of the first four states that kick off the presidential primary and caucus calendar. Our poll also indicates that he's closing the gap with former Massachusetts Gov. Mitt Romney in New Hampshire, which holds the second contest.
But rising poll numbers are also putting Gingrich in the line of fire, and verbal shots will most likely be fired at Drake University in Des Moines, site of the debate hosted by ABC News, the Des Moines Register and the Republican Party of Iowa. In the past week, the Romney campaign, as well as the campaign of Rep. Ron Paul of Texas, have stepped up attacks on Gingrich.
"The debate will be more serious, and sharper lines will be drawn," said GOP strategist and CNN contributor Alex Castellanos.
"The Republican establishment is in full panic about Gingrich's success. They fear he will blow himself up and incinerate the entire GOP ticket along with him. Newt inspires strong emotions both for and against his candidacy. I would expect Newt to be attacked consistently by the other candidates ... and to respond by saying, 'I certainly seem to be the focus of attention, almost like I am the front-runner here. I must be doing something right,' " added Castellanos, who was a top media adviser for President George W. Bush's 2004 re-election campaign and for Romney's 2008 nomination bid but who's not taking sides this cycle.
Keep your eyes on Romney, Paul, Rep. Michele Bachmann of neighboring Minnesota and former Sen. Rick Santorum of Pennsylvania, who've also criticized Gingrich, to see how forceful they are at taking on the new man at the front of the pack.
Gingrich's campaign was left for dead by many in May and June, after a number of controversies spurred some of his top advisers and staffers to quit, and that left the campaign coffers in the red. But the former House speaker has performed well in the 11 major GOP presidential debates this year, often acting as the elder statesman while many of his rivals for the nomination attacked each other. He also won over the audiences by repeatedly criticizing the moderators' questions.
Thanks to his debate performances and the fading poll numbers of contenders such as Texas Gov. Rick Perry, Bachmann and businessman Herman Cain, who suspended his campaign last weekend, Gingrich's numbers have skyrocketed.
But as we've seen, Gingrich can often be his own worst enemy.
"After this debate, we will have a good idea if Newt Gingrich has grown enough to avoid blowing himself up within the next few months," Castellanos said.
The timing is also crucial. The debate, which will be followed by a second Iowa showdown five days later, comes less than four weeks before Iowa's January 3 caucuses.
"The timing of these two debates is fortuitous. With the primary schedule abruptly moved forward, these will be the last opportunities for candidates to directly address voters before both the Christmas holiday and the important Iowa caucus. Those last impressions could help determine who wins the nomination," said Doug Heye, a GOP strategist and former Republican National Committee communications director who is in the Hawkeye State as a senior adviser to the Republican Party of Iowa.
"Fewer candidates on the stage makes a big difference. The closer you get to the altar, the less voters look at which candidate they want to date, and the more they consider who they can marry and live with for a long time," Castellanos added.
While traditional campaigning in the early voting states remains important, this cycle debates seem to have outsized importance. A poor debate performance in June helped force former Minnesota Gov. Tim Pawlenty out of the race, and stumbles in the debates this autumn were major factor in then-front-runner Perry's collapse in the polls.
"Make no mistake, debates matter. The past debates have shown how a candidate's fortune can rise or fall due to debate performance," Heye said.
The most important people watching the debate are Iowa Republicans who have yet to back a candidate.
"I'm still undecided. I am looking for a candidate that can beat Obama!" said Becky Beach, a GOP strategist and Iowa resident.
What issues is she looking for when it comes to the debate?
"It would be reducing the federal debt and cutting government spending, so we can create jobs," she said.
"While faith is important, whoever can turn the economy around matters most," added Beach, who describes herself as a social conservative.