Even then, Trump’s success was limited. He was able to push CNBC to limit the length of one debate, but only in concert with several other candidates who were unhappy. Meanwhile, he tried to bully Fox News into removing Megyn Kelly as a moderator from one debate and failed, deciding to skip the debate instead.

He’ll likely have a harder time with the general-election debates. For one thing, the debates are run not by networks but by the Commission on Presidential Debates, a nonprofit organization created after the 1984 election. It’s made up mostly of former political operatives from each party. The CPD doesn’t have any commercial incentive, and in fact it requires that networks that air the debates do so without commercial interruption. The CPD is also less concerned with ratings than for-profit networks.

Nor can Trump count on other candidates to help him pressure the CPD with him. Hillary Clinton’s campaign on Monday formally agreed to the debates and challenged Trump to do so as well. There’s often some negotiation between the candidates and the CPD about details of the debates—the height and type of lecterns, for example—but the CPD says the formats, which it released in early July, are non-negotiable. (Interestingly, Monday also saw a Politico report indicating that debate sites are preparing for the possibility of three candidates, rather than two, for the first time since 1992. Libertarian Gary Johnson is within striking distance of the 15 percent threshold required to qualify.)

If Trump skips the debate, it would be bad for the CPD. The commission’s control of presidential debates is based only on tradition and norms, and there’s nothing that could prevent a rival organization from springing up except inertia and the high barriers to getting candidates to agree to debates. If Trump skipped a debate but Johnson hit 15 percent, it’s hard to imagine Clinton would be willing to debate Johnson alone. She’d have no incentive to agree to a debate with a candidate who is not her chief rival in a setting that could hurt her.

But skipping might hurt Trump more than it would the CPD. “I did very well in the debates on the primaries. According to the polls, I won all of them,” he told Time, which is untrue in various ways. The polls he cites were unscientific, while focus groups often named other candidates the winners. More to the point, he skipped one debate altogether and forced the cancellation of another by pulling out, making the debate irrelevant.

That was in a field of 13 debates. There are only three general-election debates scheduled, so that skipping even a single one would have a big impact. One of the few recent candidates to skip a general-election debate was President Jimmy Carter, who in 1980 bailed on a debate with Republican Ronald Reagan because he objected to the presence of John Anderson, an erstwhile moderate Republican running an independent campaign. As Cornell’s Roper Center notes, that was a strategic misstep: “61 percent of registered voters in a Gallup poll said he should not have made that decision. An NBC/AP poll found 30 percent of likely voters who had heard about Carter’s choice said it made them less likely to vote for him.” It also deprived Carter of a chance to face off with Reagan, even though he believed public showdowns with Reagan would benefit him.