A historic wave of Democrats takes office in the House, Senate and state governments this January, and the economic framework that quietly underwrote the last spending boom — Modern Monetary Theory — is positioned to do it again.

MMT (the school holding that a government issuing its own currency faces no inherent debt constraint) was popularized by economist Stephanie Kelton in her 2020 book The Deficit Myth. Kelton was senior economic advisor to Senator Bernie Sanders's presidential campaigns in 2016 and 2020, and chief economist for the Democratic staff of the Senate Budget Committee late in the Obama administration. She now teaches economics and public policy at Stony Brook University, where she has been based since 2017.

What does the theory actually claim?

The core argument is simple. Deficit spending by a currency-issuing government isn't inherently bad, and household-budget analogies — the government as a family maxing out a credit card — miss the mark.

"The work that I do explains why the federal government's budget doesn't work like a household budget, and why there is more capacity to spend on priorities, whether it's healthcare, education, infrastructure, climate," Kelton says. "Whatever it is, the spending capacity is there."

That framing mattered during the early Biden administration, when supporters of what became the Infrastructure Investment and Jobs Act had to deflect warnings that recovery spending after the COVID-19 pandemic and recession would balloon the national debt.

And it may matter again. "I know that the book has been read, and the ideas have reached many of the candidates who are now getting prepared to take office in the Senate and House and across the country," Kelton says.

How did an academic fringe idea go mainstream?

One of MMT's earliest academic proponents is L. Randall Wray, now a professor at the Levy Economics Institute of Bard College, where Kelton studied under him at the University of Denver. The two later worked together at the University of Missouri-Kansas City's Center for Full Employment and Price Stability. Academia, at first, wanted nothing to do with them.

"We had funding, so we could have conferences, and we wrote academic papers," Wray says. "We gave presentations at academic conferences, and I can tell you none of that had an impact. We were trying to change the economic discipline, and it did not want to be changed."

What worked was a blog. Kelton founded New Economic Perspectives in time for the 2000s blogosphere boom and the soul-searching that followed the 2008 financial crisis. "I sort of thought it was a waste of time—this was very early in the blogosphere," Wray recalls. "But the blog took off, and really, that's how MMT got to be known."

The blog sparked public debates with prominent economists, including Nobel laureate and former New York Times columnist Paul Krugman. "By the time Krugman heard about it, I don't know the number, but I would say there were thousands of people in the blogosphere who understood MMT, and we didn't need to debate Krugman because they would do it," Wray says.

Pavlina R. Tcherneva, president of the Levy Economics Institute and author of The Case for a Job Guarantee, says the movement deliberately courted audiences beyond academia — through policymaker outreach, social media and press coverage. "It started as an academic exercise that was always very closely connected to the idea that we can have good things; that we can secure full employment, greater economic well-being, and price stability," she says.

Didn't the inflation wave discredit it?

Critics have argued since the theory's rise that applying it would drive up prices, and some have portrayed the post-pandemic inflation burst as proof. Kelton's answer: MMT always anticipated this.

She served on a Biden-Sanders economic task force in 2020 that shaped early relief-program thinking, and says she cautioned the administration about inflation without success — including through a 2021 opinion piece in The New York Times. The government can print money, she argues, but it can "run out of things to buy" if labor and productive capacity are stretched to their limits.

"Spending always has consequences, and one of the consequences can be inflation," says Kelton, who is now writing a book challenging preconceptions about inflation. "And so the whole MMT project revolves around recognizing where the limits are."

The limits can cut both ways. A Medicare for All-style system, for instance, would raise government spending but could reduce total healthcare outlays by aligning costs with other countries — a potentially deflationary shift that would require offsetting spending to avoid job losses.

The new Congress could also tackle inflation directly, Kelton argues, by curbing tariffs and winding down the war with Iran. "We were drifting back down toward 2% when the Trump administration walked through the door, and then we got immediately tariffs, and we got a war," she says.

Is MMT a policy program?

No — and Kelton insists on the distinction. "It's not an operating manual that tells you pull this lever, turn this thing, do this policy," she says. "It's just a framework." Tax-cut advocates could use it exactly as spending advocates do.

Its real influence may be ambient. "My sense is that during the Biden era, the pay-for question was not such a big obstacle, in part because the MMT conversation was everywhere," says Tcherneva. "It almost provided breathing room for people to speak about bold policies—the Build Back Better agenda."

J.W. Mason, associate professor of economics at John Jay College and senior fellow at the Groundwork Collaborative, traces a decade-long shift among Democrats: "People have much less concern about deficits as a constraint on policy than they had, you know, 15 or 20 years ago. I think that Stephanie Kelton and MMT certainly contributed to that shift."

His forecast for the incoming class: "I think you're going to see a lot of elected Democrats come in looking for a very aggressive public spending program. And I think it's going to be helpful to have some strong arguments that the federal debt is not the main thing we should be thinking about at this moment."