Come to ABC News and Yahoo! at 9 p.m. ET on Saturday to watch the Republican presidential debate in Des Moines, sponsored by ABC News, Yahoo News, WOI-TV, The Des Moines Register and the Iowa GOP. You will be able to provide real-time feedback, and to read and watch live coverage and analysis.

Amy Walter is the political director for ABC News and David Chalian is the Washington bureau chief for Yahoo News. Here is their analysis of what to look for when the candidates take the stage.

By David Chalian and Amy Walter

David Chalian: With 25 days to go before Iowa Republicans brave the January cold to head to their caucuses and cast the first votes in the 2012 GOP nomination battle, Saturday night's debate seems particularly well timed to hear the candidates' closing arguments.

Amy Walter: And ironically these candidates have spent less time in Iowa than we've seen from presidential candidates in recent years. So they are here to make the case not just to Iowans-whom they have kind of ignored for the last few months-but to a national Republican electorate still trying to figure out what kind of nominee it wants to face Obama.

So, given the stakes, what should we expect to see from the newest frontrunner, Newt Gingrich?

Chalian: First and foremost, I expect to see an inherent tension within Gingrich on stage. He has had such great success trying to stay above the fray and has made his pledge to promise only positive campaigning. It seems to me that will be in direct conflict with being the frontrunner and the likely target of nearly everyone else on that stage. Watching how he navigates through that tension will be fascinating, don't you think?

Walter: Absolutely. And, then there's the fact that Gingrich has, in the past, been his own worst enemy. Staying on message has never been his strong suit.

But, his opponents have to be careful too. As we've seen in past debates, the candidate who stays above the fray-whether that's Cain or Gingrich-has benefitted. So, I'm just as fascinated to see what Romney does. Does he try to let the other candidates take their shots at Newt or will he have to do it himself?

Chalian: A good question. And one that they have been wrestling with at his Boston campaign headquarters in recent days. I don't recall ever seeing as aggressive and overt a launch of a contrast/comparative phase of a campaign (within a nomination fight) as we saw with the Romney campaign this week. That kind of direct attack on Gingrich's record suggests to me Romney is prepared to do a lot of the heavy lifting himself Saturday and not simply rely on his fellow competitors. The lesson of Tim Pawlenty from June, right? If you launch a pre-debate attack, you better follow up on it when you get on the stage.

Walter: So, the next issue: what about the other folks on stage? This is do or die time for Rick Perry, who is spending A LOT of cash on TV ads here and is about to embark on a major bus tour around the state. He's trying to position himself as the "consistent conservative" in the race. And, of course, there's Ron Paul, The guy who came close to winning the Iowa straw poll back in August and has a serious opportunity to win it all in January.

Chalian: Perry's strategic decision to double down on capturing the social conservatives that have driven Iowa caucuses past is very interesting to me. Polls have shown that the economy is the driving force for the Iowa electorate similar to how it is nationally. This seems like an effort to capture that Huckabee vote from 2008, but the electorate may be different in terms of size and makeup on Jan. 3, 2012 than it was on Jan. 3, 2008. Many Perry aides seem to think it is the only shot they've got, but if he doubles down on the social conservative wing of the party and loses, I'm not sure he gets a ticket out of Iowa.

Paul represents the greatest question to me about this cycle. Does his additional money, organization, and poll strength compared to his 2008 run translate into a motivated army of activists who show up on caucus night. No way for us to answer that yet, but it is a very big unresolved question that hangs over this process.

Bachmann and Santorum have probably done more in-person campaigning than any of the others in Iowa, but as you said at the top - that doesn't seem to be the roadmap for success this election cycle.

Walter: So, in the end, the candidate who "wins" the debate will be the one who is able to not only engage and energize the Republican base, but one who also looks like he/she is able to translate that success beyond the primary season and into the general election. Today, polls show that Gingrich is that guy. But, will he still be that guy on Sunday morning?