Harris and Trump are both embracing policies that would raise the national debt. It’s a dangerous game.

?? Welcome to Trendlines. This is Rob Gavin filling in for Larry Edelman, who is off the road for some replacement parts. The secret word is “Joan Rivers.”

Today, we look at a problem that is getting too big to ignore.?

Plus: Why 2004 isn’t just for Red Sox fans.

Trendlines is our twice-weekly newsletter for Boston Globe Media. Click the subscribe button to keep on top of business and the economy in the region and beyond.

?? Wolf at the door

The deficit (the amount the federal government spends over what it takes in each year) and the debt (the accumulation of deficits plus interest) were noticeably absent from political debate as candidates sprint to Election Day. But the next president and Congress may not have the luxury of ignoring them.

Rising borrowing costs threaten to consume the federal budget, squeezing out funding for domestic and military programs and pushing the debt ever higher. Economists are raising alarms.

?? The big number

The nonpartisan Congressional Budget Office this month projected that the federal deficit for fiscal 2024, which ended Sept. 30, reached $1.8 trillion, up from $1.7 trillion in fiscal 2023 and $1.4 trillion in 2022.

? This time is different

Policy makers followed a Keynesian playbook during the pandemic, running the biggest deficits since World War II to support the economy until the private sector got back on its feet. It worked.

But the legendary economist John Maynard Keynes had a second part to his theory: Debt run up in bad times gets paid down in good times.?

Not anymore.

At this rate, according to CBO forecasts, the debt will outstrip economic output by 66 percent in 2054 — assuming the Trump tax cuts expire after 2025, as scheduled, and none of the goodies promised by candidates become law.

?? Why this matters

I know public finance is complicated. But it seems to me that if you keep running up your credit card and increasing your debt limit while making only minimum payments, the debt eventually crushes you.

When the day of reckoning comes is hard to predict. But it does come, as less-developed countries from Argentina to Greece have learned from sinking economies, soaring unemployment, and runaway inflation.

“We’re not at the precipice of a crisis,” said James Poterba, an MIT economics professor and president of the National Bureau of Economic Research, a nonprofit research group. “But will problems come 20 or 30 years out? Yes.”

?? Final thought?

It’s easy to dismiss deficit scolds as the boy who cried wolf. We’ve heard about a coming debt crisis for more than 30 years, and it never seems to come.

But remember a crucial part of the fable: The wolf eventually showed up.

?? Trending

Hospitals: UMass Memorial Health chief executive Eric Dickson said that without significant changes to the state's health care system, more hospitals will be forced to close.

Wall Street: Betting markets are favoring Donald Trump over Kamala Harris, but their record of accuracy is mixed.

Sports: The Boston Celtics ranked fourth on the Forbes list of most valuable NBA teams, with a valuation of $6 billion.?

?? The Closer

Here in Boston, we’re commemorating the 20th anniversary of the Red Sox’s historic comeback in the American League Championship Series. But there’s a breed of baseball fans who relished October 2004 not for the Red Sox heroic win, but for the Yankees’ epic collapse.

My father was one of them. He grew up a Brooklyn Dodgers fan and was left without a team when the Dodgers bolted for Los Angeles in 1958. For the next four years, until the expansion Mets arrived in 1962, he put his energies into rooting against the Yankees.

I sometimes thought that given the choice between his team winning and the Yankees losing, he would have taken a Yankees loss. He didn’t particularly like the Red Sox (’86, again), but he couldn’t contain his glee when they relegated the Yanks to baseball infamy as the first team to lose a seven-game series after taking a 3-0 lead.?

Baseball seasons come and go. Yankee haters are forever.

That’s it for me. Thanks for reading and I’ll be back Thursday. If you’d like to get the expanded business newsletter via email, sign up at globe.com/trendlines.