The Biden-Harris campaign appeared to buy airtime on Fox News ahead of the GOP primary debate, with ad advertisement for the Democrats’ reelection campaign running just minutes before the eight Republican hopefuls took the stage.

The ad, which acted as something of counter-programing to what the GOP hopefuls may discuss during the two-hour debate, touted what the Biden administration sees as its legislative accomplishments, like the American Rescue Plan, the Inflation Reduction Act, the CHIPS and Science Act and the Bipartisan Infrastructure Law.

The spot highlighted the economy under Biden, which is likely contrary to what the Republican primary candidates will raise on stage -- citing Biden's low marks from voters on his handling of economic issues.

–ABC News’ Isabella Murray

I’m monitoring Christie and Scott tonight. Even though the two candidates are polling similarly in the 3 to 4 percent range in FiveThirtyEight’s national polling average, they are a subject in contrasts. Although Pence has been more vocally critical of Trump recently, Christie is the most high-profile, full-on anti-Trump candidate on stage. Realistically, Christie has very little chance at the GOP nomination because he has negative net favorability ratings among Republicans. But that may mean he will focus almost entirely tonight on attacking Trump rather than making appeals to the party base. As a result, Christie could be a popular foil for the contenders on stage who have largely eschewed going after Trump, or have even defended him.

Meanwhile, Scott arguably has one of the highest ceilings of any candidate on stage. He’s not nearly as well-known to GOP voters as Trump or DeSantis, but Scott gets rave reviews from Republicans who are familiar with him. That means tonight is an opportunity for him to expand his reach and also potentially increase the share of GOP primary voters who would consider voting for him. I’ll be interested to see how much he leans into his “happy warrior” image as a means of differentiating himself from DeSantis and Ramaswamy, and whether he tries to rise above the fray to some extent if some of the other candidates — especially Christie — get into verbal fisticuffs.

–Analysis from Geoffrey Skelley

I’ll be watching Ramaswamy tonight, who will be center stage next to DeSantis, a position I did not foresee for the biotech entrepreneur when he first jumped into the race in February. But Ramswamy is on an upswing, soaring from a virtual unknown to garnering nearly 10 percent in FiveThirtyEight’s national polling average. Without Trump on the stage and with DeSantis’s polling average trending downward, is it Ramaswamy’s moment to own it?

Ramaswamy has staked his candidacy on an anti-woke, pro-capitalist message, promising to guide the country at a revolutionary moment by recognizing 10 simple truths. He’s a 38-year-old millennial leaning into the culture wars from the right who often seems to say exactly what pops into his head. This style has so far made him a major candidate. We’ll see tonight whether it appeals to voters. Thirty percent of likely Republican primary voters view him favorably, according to a FiveThirtyEight/Washington Post/Ipsos poll released today, and only 10 percent view him unfavorably. That leaves a huge chunk of voters in the middle who say they don’t know much about him and who may be seeing him speak at length for the first time during the debate. How he performs — whether it involves quoting Eminem or not — could leave a lasting impression. And a newcomer without political experience coming out of nowhere to win the Republican nomination? It’s something we’ve seen before.

–Analysis from Monica Potts

I’m tracking Burgum and Haley tonight. In another universe, the two might be top-tier contenders — a billionaire two-term governor from the heartland with great hair, and a trailblazing former governor and U.N. Ambassador long seen as a rising star in the GOP — but neither have made much of an impact on the race so far. Haley had a brief moment of prominence in February, when she was the first non-Trump candidate to jump in the race, but has since polled consistently in the low single digits. Haley will be the only woman on stage, and she may try to play to her strengths by drawing sharp foreign policy contrasts with higher-polling contenders like DeSantis and Ramaswamy (who she went after over Israel policy this week). Most of the attention Burgum has received surrounds his innovative tactic of paying people to donate to his campaign. The North Dakotan has been polling marginally better in Iowa and New Hampshire, where he’s spent millions on TV ads. If he makes it to this debate — he was in the emergency room earlier due to a basketball-related injury — his task will be to tell voters who he is, since he’s one of the least-known people on the stage, and maybe sell his Trump-free economic argument.

–Analysis from Jacob Rubashkin, Inside Elections

Members of DeSantis’s campaign are still upset about a debate memo that was prepared and published last week by a super PAC supporting the governor, a source close to the campaign told ABC News on Wednesday, describing those members of his team as “wildly irritated.”

Chief among the complaints is that the memo, which detailed suggested approaches and lines of attack, effectively handcuffs DeSantis by preventing the governor from using any of the advice on stage lest he invite attacks from opponents for using lines manufactured for him by other people.

The memo included research documents that show that Axiom Strategies, a consulting firm tied to the super political action committee, anticipated that the biggest hits to DeSantis would include his battle with Disney -- ABC News' parent company -- past comments on Ukraine, Florida's Black history standard, the culture wars and abortion.

The packet also included past comments made by presidential hopefuls attacking DeSantis on those specific subjects.

DeSantis himself has downplayed the memo, telling Fox News recently, “It’s not mine. I haven’t read it. It’s just -- I think it’s something that we have put off to the side.”

-ABC News’ Hannah Demissie, Will McDuffie and Olivia Osteen