CBO: US Federal Debt to Surpass WWII High, Reaching 120% of GDP by 2036

The United States is on a glide path to shatter its all-time record for national debt, entering uncharted fiscal territory over the next decade. According to the Congressional Budget Office's (CBO) February 2026 Budget and Economic Outlook, federal debt held by the public is projected to reach 120% of gross domestic product (GDP) by 2036.[1][9]

To understand the scale of this trajectory, economists look to historical benchmarks. The previous record for US debt-to-GDP was 106%, set in 1946 as the nation absorbed the massive borrowing required to finance World War II. Under current law, the US will surpass that post-war peak by 2030, just four years from now.[1][8]

In raw dollar terms, the expansion of the federal ledger is staggering. Debt held by the public will grow from nearly $31 trillion today to over $56 trillion by 2036. Annual budget deficits, which measure the yearly shortfall between revenues and spending, are projected to rise from $1.9 trillion (5.8% of GDP) in 2026 to $3.1 trillion (6.7% of GDP) by the end of the ten-year window.[1][2]

This structural imbalance is not primarily driven by a collapse in tax collection. In fact, federal revenues are projected to total 17.5% of GDP in 2026 and rise slightly to 17.8% by 2036—both figures sitting above the 50-year historical average of 17.3%.[1][7]

Instead, the deficit expansion is entirely driven by the outlay side of the ledger. Federal spending is projected to climb from 23.3% of GDP in 2026 to 24.4% by 2036, far exceeding the 50-year average of 21.2%. This growth is heavily concentrated in mandatory spending programs, which operate on autopilot outside the annual appropriations process.[1][3]

Social Security and Medicare are the primary engines of this mandatory spending growth, propelled by an aging population and rising per-capita healthcare costs. Between 2026 and 2036, Social Security outlays are projected to rise from 5.2% to 5.9% of GDP, while Medicare outlays will grow from 4.0% to 5.2% of GDP.[1][6]

Yet the fastest-growing category of the federal budget is neither defense nor social safety nets—it is the cost of servicing the debt itself. Net interest payments are projected to more than double over the next decade, surging from roughly $1 trillion today to $2.1 trillion by 2036.[1][5]

By the end of the projection window, interest costs will consume 4.6% of the entire US economy. To put that figure in perspective, by 2036, the federal government will spend nearly as much simply paying interest to bondholders as it does on all discretionary programs combined, including national defense, infrastructure, and education.[1][6][8]

The CBO's baseline incorporates the effects of recent major legislative and executive actions, which have dramatically reshaped the ten-year outlook. Most notably, the 2025 reconciliation act—often referred to as the One Big Beautiful Bill Act (OBBBA)—added an estimated $4.7 trillion to projected deficits over the decade.[1][7]

Initially, those new costs were partially offset by the administration's aggressive tariff policies, which the CBO estimated would generate $3 trillion in new customs revenue. However, the Supreme Court's recent ruling invalidating a significant portion of those tariffs has thrown the baseline into uncertainty.[1][4]

Without that anticipated tariff revenue, the fiscal picture darkens considerably. The Committee for a Responsible Federal Budget estimates that if the invalidated tariffs are permanently removed from the ledger and temporary OBBBA provisions are extended, the debt could reach 131% of GDP by 2036, rather than the baseline 120%.[1][2]

Looking beyond the ten-year window, the long-term outlook reveals a full-scale structural crisis. By 2056, the CBO projects that debt will hit 175% of GDP, with interest costs alone consuming an astonishing 6.9% of economic output—outpacing every other major spending category.[1][3]

This trajectory carries profound economic consequences. High and rising debt crowds out private investment, as government borrowing absorbs capital that would otherwise fund corporate expansion and innovation. It also leaves the federal government with significantly less fiscal space to respond to future emergencies, whether they be pandemics, financial crises, or geopolitical conflicts.[5][8]

The CBO's projections also assume a relatively benign interest rate environment. If yields on Treasury securities rise just one percentage point higher than projected over the next decade, it would add an additional $3.5 trillion to the national debt, pushing the 2036 ratio closer to 128% even without the tariff shortfalls.[2][7]

Furthermore, the baseline assumes that major trust funds will continue to pay full benefits even after they are depleted. The Highway Trust Fund is slated to exhaust its reserves by 2028, and the Social Security retirement trust fund faces insolvency in the early 2030s. If benefits were legally limited to incoming revenue upon insolvency, the 2036 debt would be $3.4 trillion lower—though it would trigger severe, automatic benefit cuts for retirees.[1][2]

Analysts caution against relying on technological miracles to solve the math. The CBO's rules of thumb indicate that even if an artificial intelligence boom boosts productivity growth to twice the assumed rate, it would only slightly dent the trajectory, reducing the 2036 debt ratio by a mere two percentage points.[7][9]

The paradox of the current moment is the absence of immediate market panic. As CBO Director Phillip Swagel recently noted, it is highly unusual for the United States to run such massive deficits during a period of economic expansion and moderate unemployment without triggering a financial crisis.[4]

This lack of an immediate crisis makes it politically difficult for lawmakers to enact the painful reforms—whether substantial tax increases, deep entitlement cuts, or both—necessary to alter the trajectory. The longer corrective action is delayed, the more drastic the eventual adjustments will need to be.[3][4][9]

Ultimately, the math is unforgiving. The United States has locked itself into a structural mismatch between the government services its citizens expect and the revenues it collects, shifting the burden of this imbalance entirely onto future generations.[6][8][9]