Donald Trump is not going to run as a third-party presidential candidate, even if he’s denied the Republican nomination.

There, I said it.

I’m not saying whether it would be a good idea for the GOP to deny him the nomination if he gets a plurality but not a majority of the delegates. But if it does, he won’t run third-party: He can’t afford it.

I direct you to his personal financial disclosure form, which said he had about $300 million in cash and marketable securities. That’s a lot of money! Stunningly, however, it is not enough money to run a major presidential campaign, which now clocks in at around $1 billion.

If Trump runs as a third-party candidate, the money to do so is going to have to come mostly out of his own pocket. The Republican Party's traditional donors certainly aren’t going to help him. And so far, he’s shown no ability to raise the kind of staggering totals that, say, Bernie Sanders has managed to get from small donors. Trump's campaign has raised just $25 million, of which only about $8 million comes from sources other than Donald J. Trump. He’s raised less in small contributions than Ted Cruz or Marco Rubio have.

Of course, maybe people just aren’t bothering to send money because he says he’s self-funding. Maybe in the general election, he could plead for funds and they’d open their wallets. Only … part of his appeal is that he’s so very rich that he doesn't need donations. How long does that appeal last if it turns out he doesn’t have that much money in the bank and needs donors just as much as other politicians do?

He could maybe mortgage some of his interests, borrowing a billion dollars to fund a campaign. But this seems … unlikely. For one thing, by the most generous non-Trump estimates of his net worth, that would mean mortgaging about a quarter of his assets for a near-certain loss. Or mortgaging less but spending down all his liquid assets.

And to be competitive in the general election, he would have to spend something close to that amount. His extremely lean campaign strategy won’t work in the general. He’s benefited immensely from free air time, and as of three months ago, it was estimated that about a quarter of his campaign spending actually went to companies he owns. In the general, he’s going to have to spend a lot of money on things that Trump companies can’t provide, such as campaign staff and television and radio air time. Once it’s down to two or three candidates in a general election, the media is going to make sure the other folks get as much air time as he does.

Trump, some of his detractors say, is just crazy enough to do it anyway. But I’m skeptical. He’s been bankrupt before, and at age 69, he doesn’t have a lot of time for yet another comeback. And even if he was mad enough to try, are bankers insane enough to help him? As known expert Donald Trump once noted: "These lenders aren't babies. These are total killers. These are not the nice, sweet little people that you'd think." One suspects that they might, in the end, be the ones who kill any hope of a third-party campaign.