Candidate debates have become a fixture of presidential campaigns, and they’re especially valuable in primaries. Voters get a chance to see how well candidates perform under pressure, and relative unknowns get rare exposure against the front-runners. The debates helped Barack Obama in 2008 against Hillary Clinton, and they helped Donald Trump in 2016, so it’s notable that this time Mr. Trump is threatening not to debate.

Mr. Trump and his advisers are signaling he’ll probably duck the first GOP debate, which the Republican National Committee (RNC) has scheduled for Aug. 23 in Milwaukee. Fox News is the media host, and the former President is sore because the network hasn’t always carried his rallies live. He took to Truth Social recently to say that Fox wants him to “show up and get them ratings” for the debate.

He claimed Fox wants him to debate while trying to “promote, against all hope” Florida Gov. Ron DeSantis. “Sorry, FoxNews, life doesn’t work that way!!!” he wrote.

Mr. Trump’s real motivation is probably closer to that offered by an adviser who told NBC News that “he is not going to debate unless he’s forced to by changing polling.” Mr. Trump is leading in the GOP nomination polls – “by a lot,” as he likes to say. He doesn’t want to give his opponents a chance to challenge him before a large TV audience. His advisers say Mr. Trump might even hold a rally at the same time as the debate, leaving his competitors to fight among themselves.

Mr. Trump has no obligation to debate, other than showing respect for voters. But our guess is that he knows his polling lead isn’t as invincible as he wants everyone to believe. He’s getting 50% or so in most national surveys, and many of them won’t abandon him no matter what he says in a debate. But the rest are on board because they know him as the former President or as a response to Democratic criminal indictments they see as partisan.

Millions of those voters might consider someone else who looked impressive in debates, and that’s what Mr. Trump wants to avoid. He hopes to coast to the nomination with rallies in which he can attack President Biden and tout his first-term record without anyone pointing out his failures or the risks of a second term. The GOP gave Mr. Trump a chance to debate in 2016, but he wants to deny that chance to his rivals this year.

Unlike 2016, his challengers won’t hesitate to challenge Mr. Trump in debates this time. That’s true of Mr. DeSantis, who is second in most polls and at age 44 can show a marked contrast in age with the 77-year-old Mr. Trump. Former Vice President Mike Pence will call out Mr. Trump on foreign policy and abortion. Former New Jersey Gov. Chris Christie has emerged as Mr. Trump’s most effective critic in New Hampshire town halls.

No one can force Mr. Trump to debate, but the RNC could help if it dropped its rule that every debater must pledge to support the eventual nominee. It’s a good idea in theory. But Mr. Trump might use that as an excuse not to debate, and his vow wouldn’t mean much in any case. It therefore shouldn’t be a bar to other candidates.

If Mr. Trump refuses to debate in the primaries, voters will be entitled to wonder what the former President is afraid of.

This editorial first appeared in The Washington Post on July 2, 2023. It was distributed by The Associated Press.