Tonight's debate for the 2024 Republican primaries will feature a range of candidates, including a former vice president, a self-made multi-millionaire and "anti-woke warrior", a former UN ambassador, and plenty of governors (both past and present).
The eight candidates met the criteria set by the Republican National Committee (RNC) to participate in the Fox News showdown (although reports today indicate that one of them, Doug Burgum, may miss the event after injuring himself playing basketball).
All are hoping to shine on the Fiserv Forum stage in Milwaukee, Wisconsin, at 8pm (2am tomorrow, Irish time). The second debate takes place in California a month from now.
Tonight's contenders are well aware of the chasm that separates each of them from the man whom polls have consistently ranked as the runaway frontrunner: Donald J Trump.
Most recently, YouGov and CBS found that almost two thirds of Republicans intend to vote for the former president, raising serious questions about whether the party can deliver a competitive primary.
Mr Trump will travel to Georgia tomorrow where he faces arrest on criminal charges, a development which has only increased his standing in the party. While the former president is snubbing tonight's debate, his presence will still be keenly felt.
Candidates will have to decide how closely to align themselves with his most outlandish positions, including his claims about widespread fraud during the 2020 election.
Critical opportunity
"The public knows who I am & what a successful Presidency I had," Donald Trump proclaimed on his Truth Social platform. "I will therefore not be doing the debates", he added, pointing to his "legendary" levels of support among Republican voters.
US media report that the Republican frontrunner has recorded an interview with Tucker Carlson, who Fox recently fired after it was forced to settle a court case over its mishandling of the results of the last presidential election.
There are even credible reports from CBS that, in an attempt to overshadow it, the interview might air at the same time as the Wisconsin debate.
Mr Trump joined the primaries in 2016 as a rank outsider, considered by some to be a novelty candidate, and his performances in front of the camera, including during the debates, stood him in good stead.
With less than five months until the Iowa caucuses jumpstart the Republican presidential nomination process, tonight's debate is a critical opportunity for lower-polling candidates to introduce themselves to tens of millions of voters.
Whoever survives the grueling vetting process to become the Republican nominee will, barring something unforeseen, face Joe Biden in the November 2024 contest.
So who will be taking to the stage tonight, hoping to secure that place in history, and perhaps the White House?
Ron DeSantis
Many Republicans had pinned their hopes on Florida Governor Ron DeSantis, who at just 44 has been heralded as a rising star of the hard right.
But his candidacy, announced at the end of May, has struggled to establish itself as a serious threat to the frontrunner.
Beset by rookie errors and his lack of rapport with audiences, the momentum he gained from his whopping re-election victory in November has largely evaporated.
A former naval officer, Mr DeSantis was narrowly elected in 2018 as governor of Florida after receiving the endorsement of none other than Donald Trump, with whom he shares most of his ideas.
Since then, he has cautiously - and then bluntly - distanced himself from the former president while gaining notoriety for a series of hard-right stunts on education, immigration and LGBTQ issues - including a public spat with Disney. But he's still the candidate with the best chance of beating his former endorser.
Tonight's debate is a chance for the Florida Governor to make back some lost ground.
"It's really important for the whole crowd and an opportunity for them to connect," said former Maryland Republican governor Larry Hogan, who passed on a run of his own. The stakes, he said, are highest for Mr DeSantis.
"It’s really do or die for him, make or break," he said. "Finally time to show that he’s a capable candidate. And if he doesn’t, I think this could be the end."
Nikki Haley
Nikki Haley, former governor of South Carolina and former US ambassador to the UN, is perhaps the most politically experienced woman ever to enter a Republican primary.
The 51-year-old is the sole female candidate. While she has been sharply critical of Donald Trump for continuing to claim that the 2020 election was stolen from him despite a lack of evidence, her role in the Trump administration is a definite plus, as is her executive and foreign policy experience.
She also has a crucial home state advantage in an early primary, where a win would be a huge boost to her campaign. South Carolina is the third primary, after Iowa and New Hampshire.
Vivek Ramaswamy
He's made a fortune in biotech, calls environmental activists a "religious cult" and is enjoying a surprise and substantial surge in the Republican primaries, although his outsider campaign is a long way off the front of the pack. Vivek Ramaswamy's provocative, incisive rhetoric and sustained attacks on 'wokeness' are a hit with the right wing.
At 38 he's less than half Donald Trump's age but like the former president, when he first threw his hat in the ring in 2016, is a complete political novice. The more the culture wars dominate the debate, the better he will do.
But he found himself in hot water this week when he suggested to The Atlantic that US federal agents may have been on board the planes involved in the 9/11 terrorist attacks.
Mike Pence
After years of unwavering loyalty to Mr Trump, his former vice-president Mike Pence changed his tune after the assault on the Capitol on 6 January 2021.
The 64-year-old evangelical Christian is a staunch opponent of abortion and LGBT rights. The rift between the two men means that some Trump supporters still regard the former Indiana governor as a "traitor" for failing to keep the real estate tycoon in office in 2020.
Relations deteriorated further over the weekend when Mr Pence said that he had no knowledge of then-president Donald Trump declassifying a large number of documents, a remark which contradicts the former president's main defence in one of the many court cases in which he is embroiled.
The dominant view is that Mike Pence is probably hoping to become a power broker in the party, rather than having any realistic hope of returning to the White House.
The rest of the candidates may well have similar ambitions. Of them, Chris Christie and Asa Hutchinson, two outspoken former governors, are the Republican candidates who have been the most critical of Donald Trump.
Former New Jersey governor Mr Christie, 60, is known for his combative style, portraying his billionaire opponent as self-centered and dishonest. In 2016, Mr Christie ran for the Republican nomination, but bowed out and endorsed Mr Trump.
Asa Hutchinson, 72, the former governor of Arkansas, is one of the few conservatives to openly denounce Donald Trump and has vowed to "prosecute" the former president tonight.
His campaign struggled to gain traction, but when he paid college students $20 for every person they persuaded via texts to donate $1 to the campaign, he reached the 40,000 threshold to take part in the debate.
Tim Scott is a 57-year-old senator from South Carolina, who wants to be the first black Republican president.
The grandson of a cotton picker and son of a single mother, he has written successful books, and owns several properties.
He sold his insurance firm for half a million dollars when he was elected to Congress over a decade ago.
Doug Burgum is, by his own admission, the least known of the candidates on stage tonight.
The 67-year-old North Dakota Governor, a wealthy former software executive, gave out $20 gift cards in return for $1 donations, so passing the threshold to participate tonight.
