“Reagan proved that deficits don’t matter,” Vice President Dick Cheney said when the Bush administration sought a second round of tax cuts in 2003. This fits with a rich tradition of conservative tax-cutters abandoning deficit hawkery when they want to hand money to favored groups. But some economists on the left agree with Cheney that deficits don’t matter—at least not as much as more jobs and prosperity for all—and their views are getting newfound attention because of an offhand comment by presumptive Republican presidential nominee Donald Trump.

Trump found himself well outside of mainstream thinking about deficits and debt last week when he suggested that the United States could borrow money to shore up the economy and simply ask for discounts on the debt later. Doing so would sap confidence in U.S. Treasury bonds, considered the safest financial investment in the world. The resulting interest rate rise would defeat the purpose of getting a discount on the debt, not to mention potentially triggering financial catastrophe.

Trump later explained that he was merely referring to buying back existing debt at a discount if interest rates went higher, lowering the nominal value. This is something the U.S. does routinely. But Trump went further when he told CNN on Monday, “This is the United States government… you never have to default because you print the money.”

Trump’s statement sounds a lot like Modern Monetary Theory (MMT), a tenet of economists who believe in de-emphasizing the need for deficit reduction because the U.S. controls its own currency. Balanced budgets, to MMTers, take money out of the hands of ordinary Americans who can put it to more productive use through job creation and consumer spending. The deficit only matters once you reach full employment, when overheated consumer demand can lead to inflation. But we’re nowhere near that point right now, meaning there’s plenty of room for deficits, without any possibility of default.

One MMT advocate, Stephanie Kelton of the University of Missouri-Kansas City, worked for Bernie Sanders in the Senate and now advises his campaign. But even Sanders emphasizes deficit reduction, by promoting higher taxes on the wealthy and Wall Street transactions. Kelton’s worldview, and in this instance Trump’s, goes far beyond even Sanders’s comfort level on the issue.