For the final time before the Jan. 3 Iowa caucuses, the seven men and women running for the Republican presidential nomination will face off on a debate stage tonight.

The debate will run on Fox News Channel starting at 9 p.m. eastern time. (And, yes, The Fix will be live-blogging it all!)

Republican presidential candidates, former Massachusetts Governor Mitt Romney (L) and former U.S. House Speaker Newt Gingrich (R-GA), both gesture during the Republican Party presidential candidates debate at Drake University in Des Moines, Iowa, December 10, 2011. REUTERS/Jeff Haynes

Below is our look at what to watch for — a sort of CliffsNotes to the festivities. What did we miss? Add it in the comments section!

* Can Newt hold on?: We all knew the wave of momentum propelling the former House Speaker to the front of the field would crest at some point. And there are signs — both public and private polling suggests a slight dip — that the cresting process has begun.

It’s not surprising given that Gingrich has taken loads of incoming in the past two weeks courtesy of negative ads from Rep. Ron Paul, Texas Gov. Rick Perry and the super PAC supporting former Massachusetts governor Mitt Romney — and has responded with a small ad buy of his own in which he tries to stay above the fray.(Candidates run negative ads for one reason: Because they work.)

Gingrich successfully parried off attacks from Romney and Paul in last Saturday’s Iowa debate but any signs of slippage tonight — perhaps the re-emergence of “Bad Newt”? — could help drive the looming narrative that Gingrich may have peaked a little too early.

* Romney’s return: In every debate prior to last Saturday’s gathering in Iowa, we named the former Massachusetts governor a winner. Given his relatively weak performance last weekend — $10,000 bet, anyone? — odds are that Romney will bounce back tonight.

The central question for Romney is how aggressively to go after Gingrich. His “zany” quote on the former House Speaker has drawn tons of attention over the past 24 hours but it’s not clear that Romney wants to double down on it.

What will be interesting is whether Romney tries to attack Gingrich on his record or on his temperament. Our guess is the latter because attacking on the former leaves Romney wide-open for a counter-punch on his own series of policy flip flops.

Another key question regarding Romney: He coasted through the first dozen or so debates because none of his main rivals had the stage presence and assuredness that he possesses. Gingrich has both. Saturday’s debate suggested that Romney hadn’t figured out how to break through Gingrich’s defenses. Did he and his political team solve that problem over the last five days?

* Equal time for Ron Paul?: Ask any veteran Iowa observer who the top two candidates in the state are right now and they are likely to name Gingrich and Paul. And yet, Paul has largely been treated like an after-thought in the debates to date.

In last Saturday’s debate, Paul was responsible for only 11 percent of the total words spoken in the debate — the least of any of the six candidates on stage. (By comparison, Romney accounted for 28 percent of the words spoken and Gingrich was responsible for 19 percent.)

Some of that is the fact that Paul is a very un­or­tho­dox politician and, unlike his rivals, isn’t trying to fit 10 minutes of answer into a 90-second window. But, at least a part of the inequity is also due to the fact that Paul is still regarded by many in the media — and the Republican establishment — as a fringe candidate.

While it’s hard to see how Paul winds up as the nominee — read our comparison between the Texas Republican and “Friday Night Lights” for a fuller explanation — he is clearly a major factor in Iowa. Will he be treated like one tonight?

* Rick Perry, comeback kid: Amazingly enough, the Texas governor appears to be getting a second look from Iowa voters — at least according to operatives who have seen internal polling suggesting some movement in his direction.

Perry and his super PAC — Make Us Great Again (who could be against that?) — have spent millions on the Iowa airwaves and the governor is in the midst of a 44(!)-city bus tour that will run all the way through Jan. 3.

Couple the ad spending and Perry’s aggressive Iowa-focused schedule with his not-half-bad (for him) debate performance over the weekend and we may be witnessing a bit of momentum building behind him. (Remember, too, that if Gingrich fades at all, Perry is the natural recipient of those voters as the only other viable conservative in the field.)

The key for Perry then is to over-perform expectations in tonight’s debate, which, in truth, shouldn’t be that hard to do. Perry isn’t ever going to be a great debater but if he can cast himself, as he did Saturday night, as both an outsider and a conservative, it could be enough to turn him into the big story over the final few weeks.

Of course, if past is prologue, Perry also has the potential to totally destroy any good will he has bought with Iowa voters if he can’t put together a decent performance tonight.

* Moderators as x-factor: Thinking back across this long and winding road of debates, one thing stands out: The FNC debates have featured the feistiest --is that a word? — back and forths between the candidates and the moderators.

In August, Gingrich attacked moderator Chris Wallace for asking “gotcha” questions (he wasn’t) and for “playing Mickey Mouse games” (not even sure what that means). And former Pennsylvania senator Rick Santorum complained that he wasn’t getting enough time to speak (what else is new?).

With the stakes significantly higher — the Iowa caucuses are now just 19 days away — tensions among the candidates will be even higher. How the moderators handle the back and forth — both between the candidates and between the candidates and the people asking the questions — will therefore play an even more important role in determining winners and losers.