The $39 trillion debt is set to surpass its postwar peak—and the math says Washington can’t simply cut its way out

By the time President Harry Truman left office in 1953, the United States had spent the better part of a decade paying down the debt it had run up to win World War II. The peak—reached in 1946—was 106% of GDP, a number so large that policymakers spent a generation treating it as the high-water mark of what the country could survive. That mark is about to fall. According to a new chart book, Spending, Taxes, and Deficits: A Book of Charts, released in April by Jessica Riedl, a budget and tax fellow at the Brookings Institution, the federal debt held by the public is projected to reach 137% of GDP within a decade—blowing way past the World War II peak. It’s what what budget analysts now call a “current-policy” baseline that assumes the extension of expiring tax cuts and roughly stable discretionary spending. The gross national debt itself crossed $39 trillion in March in less than five months after it hit $38 trillion, and is what the Peter G. Peterson Foundation called a “staggering” pace of accumulation with few precedents outside wartime. “Borrowing trillion after trillion at this rapid pace with no plan in place is the definition of unsustainable,” Peterson Foundation CEO Michael Peterson told Fortune when the milestone hit. The deficit’s center of gravity has shifted For most of the postwar era, deficits were episodic. They blew out during recessions and wars and contracted during expansions. But now, the 2026 deficit is on track to hit 5.8% of GDP—at a moment of relative peace and full employment—and Riedl’s current-policy baseline projects it climbing to roughly 9% of GDP by 2036, a level the U.S. has otherwise reached only during crisis: the Great Depression, World War II, the 2008 financial crisis, and the COVID pandemic. In nominal terms, the annual deficit is projected to grow from roughly $2 trillion today to $4.4 trillion by 2036. What’s driving it isn’t a mystery. Medicare alone is on trac