Tonight I’m on Pence and Hutchinson duty. Neither candidate appears to have a great shot at winning the primary — the former vice president is at 4 percent in FiveThirtyEight’s national polling average while the former Arkansas governor hasn’t even garnered 1 percent — but Pence at least has a decent chance of making a debate-night splash. Given the events of Jan. 6, 2021, Pence has the strongest claim to the anti-Trump “lane” of the primary. I wouldn’t be surprised if we saw some real fireworks between him and the GOP candidates who have been quick to jump to Trump’s defense after the bad news he has been hit with over the past year. For his part, Hutchinson will have to pull off a masterclass in persuasion and performance to gain substantial ground. In our poll with Ipsos and The Washington Post, only 6 percent of Republicans said they were even considering voting for him, much less were intending to do so. In a more fluid primary, he’d maybe have a shot at doing something about that. But with Trump as the default and other candidates leading the various anti-Trump lanes, those are really tough numbers to come back from.

–Analysis from G. Elliott Morris_

I’m watching DeSantis tonight. The Florida governor really needs a good performance tonight to reestablish himself as the main alternative to Trump after seeing his national polling average slip from 36 percent in mid-March to just 15 percent today. It will be interesting to see how much he goes after the absent Trump — which has typically been his strategy to this point — versus attacking the other not-Trumps, who are realistically his main competition these days. I’m also curious what bar DeSantis will be measured against. The popular narrative about him is that he’s kind of awkward, so maybe a quote-unquote “presidential” performance will be reassuring to people who are on the fence about him. But our poll with Ipsos and The Washington Post actually found that voters have relatively high expectations when it comes to DeSantis’s debating abilities, so maybe he needs a truly masterful performance in order to move the needle.

–Analysis from Nathaniel Rakich

Attendees seen greeting supporters outside the debate hall in Milwaukee have included former Arizona gubernatorial candidate Kari Lake, Georgia Gov. Brian Kemp and Trump's son Donald Trump Jr.

While Ramaswamy is still "unlikely" to visit the spin room following the debate, his wife, Apoorva Ramaswamy, his communications director and senior adviser Tricia McLaughlin, two other team members and an undisclosed "special guest" will be there on his behalf, according to McLaughlin.

The spin room is the space where campaigns highlight their candidate and attack their opponents after the debate. Many candidates themselves head there after they take the stage.

-ABC News' Kendall Ross

Recent initial primary debates have involved a lot of candidates — 17 for Republicans in 2016 and 20 for Democrats in 2020 — across two debates, either on the same night or across two evenings. To lead off the 2024 cycle, Republicans will have a more intimate affair, with eight contenders taking the stage tonight. That number could’ve been slightly larger, however, as nine GOP candidates met the RNC’s debate qualification criteria for polls and donors. But Trump isn’t participating, having refused to sign a mandated loyalty pledge promising to support the eventual GOP nominee in the general election, so there will be only eight lecterns on stage.

Eligible participants either earned 1 percent support in three national polls or at least 1 percent in two national polls and two polls from the first four states voting in the GOP primary (each coming from separate states), based on surveys that meet certain criteria for inclusion. They also attracted donations from at least 40,000 unique contributors, with at least 200 donors from 20 or more states and/or territories.

Meeting these criteria was straightforward for most of the candidates, as by the end of July, seven (including Trump) had enough qualifying polls and donors to make the stage. Lagging behind, Pence became the eighth eligible contender when his campaign announced on Aug. 7 that he brought in enough unique donors. Hutchinson had enough surveys in hand by late July, but he only announced on Sunday that he had reached the 40,000 donor mark, coming in just under the deadline.

But there was last-minute drama, as businessman Perry Johnson and Miami Mayor Francis Suarez each said they had qualified, only for the RNC to leave them off its final list of participants. Johnson in particular may have a bone to pick, as he claimed that the RNC initially indicated that he had enough polls, and our analysis suggests he did, too. Larry Elder, who along with Johnson hasn’t met FiveThirtyEight’s criteria for being considered a major candidate, also claimed he had made it,> but one of the polls he cited did not have a large enough sample size to meet the RNC’s criteria. Johnson and Elder announced yesterday that they were suing the RNC. Suarez, Johnson, Elder and Hurd all had enough donors to make the stage but, controversially or not, lacked the polls in the end.

-Analysis by Geoffrey Skelley of FiveThirtyEight