Who knows if he’s serious, but Donald Trump now says he might pull out of a Dec. 15 Republican presidential debate unless CNN, the cable network broadcasting the event from Las Vegas, pays him $5 million.

Trump says he would donate the money to veterans’ charities (naturally). But the idea — which he contemplated onstage for more than eight (!) minutes Monday night during a rally in Macon, Ga. — is preposterous for several reasons.

For starters, “there is absolutely no precedent for this,” said Alan Schroeder, a journalism professor at Northeastern University and the author of a 2008 book about presidential debates, which he is currently updating during a sabbatical. “One of the things about debates that’s a positive is they’ve always been separate from the whole financial aspect of campaigning. This is extortion. I hope CNN calls his bluff.”

CNN declined to respond to Trump's remarks.

The debate stage is supposed to be a level playing field for all candidates. The wealthiest and most influential politicians enjoy all sorts of advantages on the campaign trail; for one thing, they can rent venue after venue for rally after rally, saying anything they want with no one to challenge them. Trump is a master of this.

But in a debate, opponents and — critically — moderators are there to push back and follow up. How are voters supposed to have any faith in the process if the network that carries the debate and supplies the moderators is paying one of the candidates?

Trump has floated the notion of a profit-sharing arrangement before. He told ABC in November that “the networks are making a fortune with the debate. I’d like the see the wounded warriors and the veterans get some of the profits.”

The idea is quintessential Trump. The man, after all, loves to talk about TV ratings and, more specifically, how good he is at delivering them.

The networks airing debates have not made finances public, but this year’s forums are widely reported to be unusually good money-makers — on the Republican side, anyway. For CNN’s first GOP debate in September, for instance, the network charged 40 times its normal advertising rate, according to Ad Age.

Advertising rates are largely a function of ratings, and the primary debate ratings have been yuuuge. Trump is undeniably a major reason for the spike, though his appeal appears to be waning; each of the last three debates has attracted a smaller audience than the one before it.

Trump’s argument is that the networks are making money on his appearances, so he should get to decide where at least some of that money goes.

But the reality is that Trump needs the networks as much as they need him. He has, after all, subsisted largely on free media — i.e. interviews with the press. Where else can he speak to 20 million people at once? Even he acknowledged, during his address in Macon, that skipping a debate could hurt him in the polls.

And perhaps the biggest problem with Trump’s proposal is that it overlooks a fundamental difference between media companies and presidential candidates. Media companies — the for-profit ones, anyway — are supposed to make money. Presidential candidates are supposed to be public servants seeking an office that will, in many cases, pay them far less than what they earn in the private sector.

When Trump complains about not getting a cut of debate revenue, he certainly doesn’t sound like a future president. He sounds like what he's always been: a businessman.