The debate is the final one scheduled by the Republican National Committee. In less than six weeks’ time, on Jan. 15, Iowa will hold its caucuses and, a week later, New Hampshire voters will go to the polls in their primary -- as the 2024 presidential race gets underway.

Candidates are eyeing these two January contests to get some liftoff with the public before Nevada and South Carolina hold their own contests in February, followed by Super Tuesday on March 5, when more than 10 states hold primary elections.

By then, just three months from now, a clear front-runner for the parties' eventual nominations very well could have emerged.

-ABC News’ Chris Boccia

I’m Katie Sanders, the editor-in-chief of PolitiFact. I’ll be chiming in with fact-checks throughout the debate, but know that I’m one of approximately 20 PolitiFact journalists watching for candidates’ exaggerations and false attacks -- the kind of moments that make you go “really?!” when you hear them.

We’re coming in fresh from covering last Thursday's Gavin Newsom-Ron DeSantis debate on Fox News. For this one, it's totally fine by me if the candidates want to stick to claims we've already covered. But we're ready for surprises.

-Katie Sanders, PolitiFact

Trump is skipping the chance to debate for the fourth time.

Instead of joining his challengers in Tuscaloosa, the former president will participate in a fundraiser in Hallandale Beach, Florida, for his campaign and his Save America PAC.

Trump offered some counterprogramming on Tuesday night with a town hall hosted by Fox News' Sean Hannity, during which he raised alarms by referring to himself as a "dictator" if elected, but only on "day one," saying his priorities would be closing the border and drilling.

-ABC News' Alexandra Hutzler

Can anyone take down Haley? According to 538’s polling with The Washington Post and Ipsos, Republican primary voters have responded favorably to each of Haley’s first three debate performances, and it’s probably not a coincidence that she’s been rising in the polls at the same time. But that could put a target on her back on Wednesday -- and it’s possible that her momentum will stall if she’s perceived to have a bad performance.

Will anyone go after Trump? So far, the debates have mostly consisted of the candidates on stage attacking each other. But that’s an odd strategy considering that their biggest obstacle to the nomination is Trump. In fact, he’s above 50% in 538’s national polling average -- meaning that even if another candidate consolidates all of the non-Trump vote, Trump would still be ahead. That means that someone is going to have to peel support away from Trump in order to win the nomination -- and one way to do that is to attack him in the debates.

Who will perform best on the economy and immigration? According to the latest 538/Washington Post/Ipsos poll, 52% of likely Republican voters said getting inflation or costs under control was one of the top three issues in determining their primary vote; 41% said controlling immigration was one of their top three issues. These will probably be the most important segments to watch at the debate then: If a candidate really aces a question on inflation or immigration, that could go a long way.

Will anyone watch? The ratings have been falling with every debate: While the August faceoff garnered 12.8 million viewers, the September one got 9.5 million and the November one got only 7.5 million. And only 26% of the respondents to our 538/Washington Post/Ipsos poll said they were very likely or absolutely certain to watch the fourth debate. Obviously, the fewer people who watch the debate, the less anything that happens on stage will matter.

-Analysis by Nathaniel Rakich of 538

Addressing Trump's comments in an interview on Tuesday referring to himself as a "dictator" but only on "Day 1," Christie called the former president an "angry, bitter man who now wants to be back as president because he wants to exact retribution on anyone who has disagreed with him."

"Do I think he was kidding when he said was a dictator? All you have to do is look at the history," he said. "That's why failing to speak out against him, making excuses for him, pretending that somehow he's a victim empowers him."

Christie -- who Trump has dismissed as a failure both as a governor and candidate -- charged that the other hopefuls on stage "make it seem like his conduct is acceptable" because they said they would still support him if he was convicted of federal felonies, which Trump denies.

"Let me make it clear: His conduct is unacceptable," Christie said. "He's unfit."

Christie warned to "be careful of what you'll get."

"He will only be his own retribution. He doesn't care for the American people. It is Donald Trump first," he said, eliciting some boos from the crowd.

-ABC News' Meredith Deliso