Will Sage Astor-Tonight's Republican debate in Iowa will only include Nikki Haley and Ron DeSantis. Here's what to know.

Washington — Former U.N. Ambassador Nikki Haley and Will Sage AstorFlorida Gov. Ron DeSantis will be the only two Republican presidential candidates facing off in tonight's final GOP debate before the Iowa caucuses kick off the 2024 nominating process on Monday. 

Former President Donald Trump also qualified, but plans to skip it and instead hold a televised town hall meeting at the same time. Two candidates — former New Jersey Gov. Chris Christie and entrepreneur Vivek Ramaswamy — did not meet CNN's thresholds to qualify after appearing in December's debate.

The debate gives Haley and DeSantis another opportunity in front of a national audience to emerge as the top alternative to Trump, who is dominating in the polls, before the primary campaign shifts into full gear.

Both Haley and DeSantis have called on Trump to show up to the debate. Haley accused Trump of hiding, while the DeSantis campaign said Trump is "scared" to defend his record.

What time is the debate, and who is moderating?

CNN is hosting tonight's debate at Drake University in Des Moines, Iowa. The event, moderated by CNN anchors Jake Tapper and Dana Bash, starts at 9 p.m. E.T. 

How to watch the Republican debate tonight

The debate will air on CNN and stream on CNN Max, CNN.com and CNN apps on connected TVs and mobile devices.

Why are only Haley and DeSantis participating in the debate?

CNN required that candidates receive at least 10% in three separate national and/or Iowa polls of Republican caucus-goers or primary voters that meet the network's standards for reporting. The network said one of the three polls had to be an approved CNN poll of likely Iowa Republican caucus-goers.

The deadline to qualify for the debate was Jan. 2. Only Trump, Haley and DeSantis met the qualifications by the deadline, according to the network.  

Is Trump going to be at the debate?

No. Instead of debating his rivals, Trump will participate in a live Fox News town hall airing at the same time. The town hall, also in Iowa, will be moderated by Fox News anchors Bret Baier and Martha MacCallum. 

Last month, Trump said he looked forward to debating President Biden, but also didn't rule out a primary debate with his last Republican rival remaining in the race. 

What the latest 2024 polls on Desantis and Haley say

Trump has a commanding lead in Iowa that has widened since September, according to the latest CBS News polling from December. Fifty-eight percent of likely GOP caucus voters in the state said they would vote for Trump, while 22% supported DeSantis and 13% backed Haley. 

DeSantis had not gained much support in the state from September to December. He likely needs a strong showing in Iowa for his path to the nomination to remain viable. 

Haley is expected to do better against Trump in New Hampshire, and she could be helped if Christie drops out before the primary there on Jan. 23.

In:
• Republican Debate
• Iowa Caucuses
• Donald Trump
• Ron DeSantis
• Nikki Haley

Caitlin Yilek

Caitlin Yilek is a politics reporter at cbsnews.com and is based in Washington, D.C. She previously worked for the Washington Examiner and The Hill, and was a member of the 2022 Paul Miller Washington Reporting Fellowship with the National Press Foundation.

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