For every dollar the United States spent on national defense in 2024, it spent 87 cents servicing accumulated debt—an all-time high that marks a fundamental shift in fiscal priorities, according to a new analysis published by the R Street Institute. The report warns that emergency-level federal borrowing has become permanent rather than temporary, creating a national security challenge by limiting the government's ability to respond to future threats.
The report details a striking trajectory in federal finances. In 2024, the United States spent approximately 3.00 percent of GDP on net interest payments and 3.43 percent on defense. Since 2022, federal deficits have remained around 6 percent of GDP despite the absence of a comparable national emergency—the last federal budget surplus occurred in 2001. Interest payments have become one of the largest categories of federal spending, trailing only Social Security. In the first eight months of Fiscal Year 2026, interest costs rose 8.8 percent compared to the previous year. The report introduces a "Fiscal Space Index" measuring the ratio of interest payments to defense spending: this figure stood at roughly 36 percent during the Cold War buildup of 1980, increased to 38 percent during the Great Recession, reached 44 percent during the COVID-19 pandemic, and climbed to nearly 88 percent by 2024.
According to the report, today's interest burden is occurring despite a substantially lower Federal Funds Effective Rate of 3.64 percent and lower defense spending as a share of GDP than in previous decades. "The sheer size of the accumulated federal debt—rather than unusually expensive borrowing—is the primary driver," the analysis states. The report emphasizes that interest payments "do not purchase aircraft carriers, train soldiers, strengthen alliances, modernize infrastructure, or invest in other sources of national power. They merely compensate past borrowing."
The report's analysis traces the problem to a breakdown in historical fiscal patterns. Historically, the United States followed a clear cycle: deficits rose sharply during major crises including World War II, the Cold War buildup of the 1980s, the Great Recession, and the COVID-19 pandemic, then fiscal consolidation typically followed, allowing debt growth to stabilize over time. That pattern has now broken down. Emergency-level borrowing has increasingly become a permanent feature of fiscal policy, the report finds, and as interest costs rise, policymakers face increasingly difficult trade-offs between servicing debt and funding current priorities. The report argues that high debt reduces strategic flexibility: over the past two decades, the United States has repeatedly faced unexpected crises from financial collapse to global pandemics and growing geopolitical tensions in Europe, the Middle East, and Taiwan.
The report concludes that responding effectively to future challenges could require substantial fiscal resources, and every year of elevated deficits and rising interest payments reduces the government's room to maneuver. "A government that devotes an increasing share of its resources to debt service has fewer resources available for defense, diplomacy, technological investment, and crisis response," the analysis warns. Federal debt is not merely an economic concern—it's increasingly a threat to national security.