The economist counting down to America's debt doomsday

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He was once called “Dr. Doom and Gloom” on Wall Street. Not everything has changed for Kent Smetters, who runs the Penn Wharton Budget Model. His economic predictions remain gloomy, but imminent doom isn’t around the corner.

In his view, doom will land on America’s doorstep between 2045 and 2050, the breaking point for the U.S. economy. That’s the moment when, as Smetters sees it, the cost of interest payments on the national debt would become so large for the federal government that even a broad-based tax increase wouldn’t cut it anymore.

At that point, Smetters says, the U.S. government would enter either an explicit or implicit default, both with calamitous consequences. An explicit default renders the U.S. a global deadbeat. An implicit default theoretically occurs through debt monetization — which jacks up inflation — or by trimming Social Security and Medicare payments.

“This is when panic starts happening. This is the loss of faith in government,” Smetters told me. “That's what's doomed other societies as well. Before us, you can go all the way back to Rome, to France, Spain, the U.K., and Germany. Almost every empire has been taken down by debt.”

Smetters is part of a familiar group of fiscal hawks cycling in and out of Washington, which has all but surrendered to a national debt that swells in size with every passing day. The gross U.S. federal debt surpassed $38 trillion in October, per data from the Treasury Department. Put another way, total U.S. debt has grown by $66,225 each second so far in 2025, according to the Joint Economic Committee in Congress.

Those are staggering figures. But the growing U.S. debt isn’t likely to be tamed anytime soon. President Donald Trump and a GOP-led Congress brushed aside concerns about fiscal discipline when they muscled through the so-called “Big Beautiful Bill” with a $3.4 trillion price tag this summer. 

‘Neither party has any credibility’

Tackling the debt has periodically cropped up as a priority in Congress. The most well-known effort in recent times was the bipartisan Simpson-Bowles Commission in 2011. Lawmakers in both chambers convened to strike an austerity deal the country could live with. It didn’t take long for those belt-tightening efforts to collapse, triggering automatic cuts in the ensuing years. A striking resignation has sunk in even among hardened spending-battle veterans.

“Frankly neither party has any credibility on that issue anymore,” Virginia Democratic Sen. Mark Warner, who sat on the Simpson-Bowles panel, told me a couple years ago. The U.S. debt at the time registered $32 trillion, a ballooning amount he believed was going to “come back and bite us.”

Warner, a prominent Democratic centrist, said then that he’d been compared to a “debt Cassandra” for raising warnings about the debt that were landing on deaf ears. Cassandra was a figure in Greek mythology who delivered prophecies of impending disasters that no one believed.  

Tragic tales aside and another $6 trillion in debt later, Smetters similarly acknowledged there is a “boy who cries wolf” problem in consistently prodding policymakers to restrain federal spending. The U.S. accumulates the vast portion of its debt through spending on programs like Social Security and Medicare.

Jason Furman, a former top economic adviser to President Barack Obama who is now a professor at Harvard University, recently pointed out on social media that “being an Anglo-Saxon country is not great for borrowing costs right now.” He posted a chart showing U.S. 10-year bond yields hovering at 4%, squarely in the top five of advanced countries. Greece has lower 10-year yields at 3.3%. It means the Greek government can raise money through bonds at much better terms than the U.S., a remarkable reversal of the market pecking order.

In an interview, Furman said the U.S. and the U.K. are in a “toxic” league of their own with unchecked spending habits.

Bond markets may be the last enforcement mechanism to force national governments to change course. U.S. bond yields spiked after Trump rolled out his so-called reciprocal tariffs in April, leading him to temporarily back down. The president still enacted them on almost every country four months later. This time, bond markets didn’t go haywire.

“I'm a little bit surprised,” Furman told me. “I wouldn't have thought this is what would happen to bond markets.” He said one possible explanation for the muted reaction is investors’ faith that the Federal Reserve would ride to the rescue with lower interest rates to juice growth.

Even in the middle of enormous economic uncertainty from stalling jobs growth and trade wars in every direction, U.S. financial markets are unfazed. The Dow Jones Industrial Average and the S&P 500 both notched new records last week. That hasn’t gone unnoticed by Trump, who said Wednesday that he believes the stock market will keep climbing to new highs.

“In the meantime, they just keep believing that the government will eventually get a fix done,” Smetters said of investors. “It all comes down to, when [do] capital markets stop believing that government will ever get its act together?”