I call it priming the pump! (Photo by Jabin Botsford/The Washington Post)

President Trump thinks he invented a term “a couple of days ago” that he has been using for months and that economists have for more than a century, and it wasn't even the least accurate thing he said in his latest interview.

Now, everyone is understandably laughing at Trump's history of the phrase “priming the pump.” That, of course, is the long-standing idea that the government should fight recessions by cutting taxes and increasing spending. It really entered the lexicon in the 1930s — that's the first time the Economist used the term — but it goes back to at least 1916. Trump, though, has some alternative facts. “Have you heard that expression used before?” he asked the Economist, before explaining that “I haven't heard it ... I came up with it a couple of days ago and I thought it was good.” This is puzzling. First off, Trump's question doesn't make any sense on its own terms. How could they have heard of it if he just came up with it? And second, how could he think he just coined it when he used the very words “priming the pump” back in March and December?

Who knows.

But the bigger point is that Trump doesn't show any more ability to distinguish fact from fan fiction when it comes to his policies, either. He said in the interview, for example, that his health-care plan means that “we're going to have much lower premiums, and we're going to have much lower deductibles.” This is false. The Brookings Institution, for one, estimates that on an apples-to-apples basis — holding the generosity of insurance plans and the age of the insurance pool constant — Trumpcare would actually increase premiums by 13 percent. And the nonpartisan Kaiser Family Foundation says that it would increase the average deductible by $1,550. Not to mention the 24 million people the Congressional Budget Office says would lose coverage mostly as a result of the bill's big cuts to Medicaid and the Affordable Care Act's subsidies. Trump seems to think that just saying his plan keeps his promises — such as having “insurance for everybody"—is the same thing as actually keeping them.

It's no different with taxes. Trump has claimed that he will “massively” cut taxes for the middle class, but even the most generous analyses conclude the opposite — he'd help the rich much more than anybody else. But Trump brushed this concern aside when the Economist brought it up by simply saying “I don't believe that,” since top earners would lose a lot of deductions under his plan. Never mind that they wouldn't need those deductions as much when they'd be paying a much lower rate. Trump just repeats that his plans will be great for everybody, that more and more people love it, and, impossible as it sounds, that it's getting better and better all the time. If you want more detail than that ... well, did he mention that it's great?

This is the kind of thing that only works as long as your plans haven't passed. Because once they do, there's no hiding from the fact that what you said would happen is the opposite of what is actually happening.

Not that Trump would necessarily notice. He might be too busy coming up with new economic terms such as “tax cut” and, um, “cutting taxes.”