So very easy to clear this all up. Donald Trump just has to pay for his presidential campaign himself. Like he promised.

Trump is not a particularly generous guy. A Washington Post analysis of the 4,844 charitable contributions he claimed to have made over the last five years found that they were heavy on free rounds of golf at Trump courses and light — well, actually nonexistent — when it came to personal money. A lot of the expenses he claimed to be covering during the primary campaign were actually bills for the rental of offices in Trump buildings or flights on Trump planes.

(Wait a minute — if you donate to the Trump presidential campaign, is there any chance the money could be used to pay back a Trump loan for money to pay rent in a Trump office tower? Just asking.)

Nobody has ever spent anything close to $1 billion to fund his or her own political campaign. Ross Perot spent the 2016 equivalent of $110 million to run for president as an independent in 1992, and that seems to be the record. But the price tag on this year’s race hasn’t gone up since the campaign started, and Trump promised. It’s sort of his point.

Maybe he doesn’t have the money. Cynical minds have suggested that he’s refusing to make his tax returns public because he’s actually worth way, way less than the $10 billion he keeps claiming. What if it’s only $1 billion? Or a few million? Once, years ago, I referred to him as a “thousandaire” and the reaction was … harsh.

There’s certainly something in those documents he doesn’t want us to know. But I believe I speak for a great many Americans when I say that if Donald Trump announced he was going to keep special interests out of his campaign by paying for the whole damn thing himself, we would be so impressed that the tax return issue would completely disappear.

Coming up with a billion dollars over six months would certainly be a challenge. Hardly something you could expect an ordinary person to do. Even an ordinary person with $4 billion — whoops, $10 billion. But isn’t the whole attraction of Trump supposed to be his specialness? Couldn’t he make a deal?

Doesn’t matter if it’s hard. Doesn’t matter if it’s a simple-minded idea. Simple-minded ideas are what Donald Trump is all about. People, the next time you hear him brag about his incredible, unique, no-Washington-insiders campaign, feel free to yell back:

Show me the money.