GOP presidential candidates start declaring their loyalty

With the first GOP presidential primary debate just 13 days away, Republican candidates are racing to earn a spot on stage -- but nabbing a coveted podium comes with strings, including a vow to back the ultimate nominee, whoever he or she might be.

Meanwhile, former President Donald Trump's entourage at the Iowa state fair is packed with Floridian endorsers in a swipe at Gov. Ron DeSantis as he calls on Republicans to fall in line behind his march back to power.

And in Ohio, the state Supreme Court set a date to hear a case over the state's proposed six-week abortion ban.

Here's what to know from the trail on Thursday.

Candidates start signing loyalty pledge -- but not Trump

Four GOP candidates signed the Republican National Committee's loyalty pledge to ensure a spot on the Aug. 23 debate stage. But Trump was not one of them.

DeSantis, entrepreneur Vivek Ramaswamy, former South Carolina Gov. Nikki Haley and North Dakota Gov. Doug Burgum all signed the pledge, in which the candidates vowed to "honor the will of the primary voters and support the nominee in order to save our country and beat Joe Biden" and "not seek to run as an independent or write-in candidate."

Trump, still the de facto leader of the GOP despite two impeachments, three indictments and three consecutive disappointing election cycles for Republicans, said Wednesday that he would not sign the pledge as he hints he could skip the first two debates altogether.

"I wouldn't sign the pledge. Why would I sign a pledge if there are people on there that I wouldn't have. I wouldn't have certain people as somebody that I would endorse," Trump said on Newsmax, though he didn't specifically say who he would not endorse.

The former president has consistently downplayed the importance of primary debates for his campaign given his yawning polling lead, saying appearing on stage would only give candidates with less support the chance to take potshots at him.

Trump brings Florida entourage to Iowa

Trump, along with most of the rest of the GOP presidential field, is heading to Iowa. But he's not going alone.

Trump will bring with him nine Florida Republicans -- Reps. Gus Bilirakis, Byron Donalds, Matt Gaetz, Carlos Gimenez, Anna Paulina Luna, Brian Mast, Cory Mills, Greg Steube and Mike Waltz -- who have endorsed him over their home state governor.

The move underscores Trump's sway over the party at large, even as he goes after perceived enemies like popular Iowa Gov. Kim Reynolds, as well as his focus on belittling DeSantis, who has long been considered the most significant challenger to Trump despite his inability to close the polling gap that separates them.

Reynolds opens the door to a pre-caucus endorsement

Speaking of Reynolds, the Iowa governor has previously insisted that she will not issue an endorsement before her state's famous caucuses early next year.

But Thursday, she appeared to leave the door open just a crack to giving her imprimatur before voters head to the polls.

"Well, I don’t know," she told radio host Hugh Hewitt when asked whether she would endorse a candidate before the caucuses. "I've said I want to stay neutral. I want [the candidates] to come. I'll be anxious to see what happens with the first debate. But I'm always wary to never say never. But right now, we’re going to stay neutral."

Trump has gone after Reynolds for appearing at events with DeSantis, but the governor has not returned fire.

Ohio Supreme Court sets date to hear arguments over abortion ban

Ohio's Supreme Court said Thursday that it will begin hearing arguments on Sept. 27 over the state's six-week abortion ban.

The ban earlier this year was put on hold by a lower court and is not in effect.

The announcement comes two days after Ohio voters rejected an effort to raise the threshold for a constitutional referendum to pass from a simple majority to 60% -- just months before a referendum on adding abortion protections to the state constitution.

ABC News' Kendall Ross and Isabella Murray contributed to this report.