There is a comforting story about the debt ceiling that goes like this: Back in the 1990s, the U.S. was shrinking its national debt at a rapid pace. Serious people actually worried about dislocations from having too little government debt. If it hadn’t been for two wars, the tax cuts of 2001 and 2003, the housing meltdown, and the subsequent financial crisis and recession, the nation’s finances would be in fine condition today. And the only obstacle to getting there again, this narrative goes, is political dysfunction in Washington. If the Republicans and Democrats would just split their differences on spending and taxes and raise the debt ceiling, we could all get back to our real lives. Problem solved.

Except it’s not that way at all. For all our obsessing about it, the national debt is a singularly bad way of measuring the nation’s financial condition. It includes only a small portion of the nation’s total liabilities. And it’s focused on the past. An honest assessment of the country’s projected revenue and expenses over the next generation would show a reality different from the apocalyptic visions conjured by both Democrats and Republicans during the debt-ceiling debate. It would be much worse.

That’s why the posturing about whether and how Congress should increase the debt ceiling by Aug. 2 has been a hollow exercise. Failure to increase the borrowing limit would harm American prestige and the global financial system. But that’s nothing compared with the real threats to the U.S.’s long-term economic health, which will begin to strike with full force toward the end of this decade: Sharply rising per-capita health-care spending, coupled with the graying of the populace; a generation of workers turning into an outsize generation of beneficiaries. Hoover Institution Senior Fellow Michael J. Boskin, who was President George H.W. Bush’s chief economic adviser, says: “The word ‘unsustainable’ doesn’t convey the problem enough, in my opinion.”

Even the $4 trillion “grand bargain” on debt reduction hammered out by President Barack Obama and House Speaker John Boehner (R-Ohio)—a deal that collapsed nearly as quickly as it came together—would not have gotten the U.S. where it needs to be. A June analysis by the Congressional Budget Office concluded that keeping the U.S.’s ratio of debt to gross domestic product at current levels until the year 2085 (to avoid scaring off investors) would require spending cuts, tax hikes, or a combination of both equal to 8.3 percent of GDP each year for the next 75 years, vs. the most likely (i.e. “alternative”) scenario. That translates to $15 trillion over the next decade—or more than three times what Obama and Boehner were considering.

You start to see why, absent signs of a serious commitment to deficit reduction, the rating services are warning they may downgrade the federal government’s triple-A rating even if Congress does meet the Aug. 2 deadline. Fortunately, our debt hole is escapable. But digging out requires that leaders of both parties come to terms with just how deep it is.

The language we use is part of the problem. Every would-be budget balancer in Washington should read “On the General Relativity of Fiscal Language,” a brilliant 2006 paper by economists Laurence J. Kotlikoff of Boston University and Jerry Green of Harvard University (available online from the National Bureau of Economic Research). The authors write that accountants and economists have something to learn from Albert Einstein’s theory of relativity, about how measured quantities depend on one’s frame of reference. Terms such as “deficit” and “tax,” they write, “represent numbers in search of concepts that provide the illusion of meaning where none exists.”