The Interest on America's National Debt Now Exceeds the Defense Budget. The Big Beautiful Bill Would Make It Worse.

For the first time in modern budget history, the United States government paid more to service its national debt last fiscal year than it spent on national defense. Net interest on the federal debt reached $882 billion in fiscal 2024; defense discretionary spending came to $874 billion. The gap was $8 billion — barely rounding error at the federal scale — but the crossing of that threshold was real, and it arrived precisely as Congress was advancing a budget package projected to deepen the debt by $3.8 trillion over the next decade.

The Senate now holds the One Big Beautiful Bill. The conversation about whether three Republican dissenters can be brought around is important. So is the question the monthly budget numbers are forcing: what does that bill cost on top of what the country already owes?

A Milestone Nobody Wanted to Announce

The comparison to defense spending is not accidental. For decades, the defense budget has served as Washington’s implicit reference point for federal priorities — the floor below which other spending negotiations rarely go. In the 1990s, net interest on the debt consumed roughly 15 percent of federal revenues. After the 2008 financial crisis, near-zero interest rates made vast amounts of new borrowing cheap to carry. The government issued trillions of dollars in debt between 2020 and 2022 at coupons below 1.5 percent on the 10-year Treasury note. The payment on that debt stayed manageable even as the principal grew.

That era ended when the Federal Reserve raised rates. Long-term Treasury yields followed. When Moody’s became the last major credit agency to strip the United States of its AAA rating earlier this month, the agency’s analysts put a specific ratio to what they were seeing: by 2035, under any plausible continuation of current fiscal policy, interest payments would consume approximately 30 percent of federal revenues. That figure is roughly triple the ratio from the early 2000s.

Moody’s was citing a trend the budget numbers had already confirmed. The fiscal year 2024 data was not ambiguous: $882 billion in net interest against $874 billion in national defense. Both numbers were larger than Medicare. Both were larger than Social Security’s annual expenditure growth component. The interest payment, unlike defense or entitlement spending, cannot be reduced by policy choice — it is the cost of debt the country has already incurred.

The immediate market reaction to the Moody’s downgrade showed up in Treasury yields. The 10-year note, which had already climbed through 2025 and into 2026, reached fresh highs in the days following the announcement. Federal Reserve Chair Kevin Warsh addressed this directly in his first public speech since taking office: “Long-term rates reflect the market’s assessment of inflation expectations and fiscal risk over years and decades. When those rates move in response to a change in the fiscal trajectory, that is the market doing what markets are supposed to do.”

Warsh’s message was clear: the Fed will not cut rates to relieve the fiscal pressure. Whatever happens in bond markets as a result of choices in Congress is Congress’s to own.

The Compounding Problem: Old Debt Rolling Over to New Rates

The interest bill does not only grow when the government borrows more. It also grows when existing debt matures and must be refinanced at current, higher rates — what debt analysts call rollover risk.

The Treasury manages issuance across a range of maturities: 1-month bills, 2-year notes, 5-year notes, 10-year notes, and 30-year bonds. The average maturity of the total federal debt sits at approximately six years. That means a substantial share of the debt issued during the low-rate years of 2019 through 2022 — much of it carrying coupons below 1.5 percent — will reach maturity and require refinancing within this decade.

When a 2-year note issued in 2022 at 0.75 percent comes due and Treasury must issue a replacement at today’s rates, the annual interest cost on that tranche of debt rises by three to four percentage points. Multiply that effect across the full volume of debt rolling over annually — the Treasury issues $7 to $9 trillion in gross debt per year, much of it refinancing prior obligations — and the arithmetic becomes expensive quickly.

The Congressional Budget Office projected in its January 2025 budget outlook that net interest on the federal debt would rise from $882 billion in fiscal 2024 to over $1 trillion per year by fiscal 2026, and would continue climbing toward the end of the decade under current law — before any new legislation was factored in. The projection assumed rates would stabilize near their then-current levels. If rates rise further, or if confidence in U.S. fiscal credibility erodes, the baseline will prove too optimistic.

What $3.8 Trillion in New Debt Adds to That Baseline

The CBO’s preliminary score of the House-passed Big Beautiful Bill puts the total ten-year deficit impact at approximately $3.8 trillion. That figure captures the changes to revenues and outlays that the bill directly enacts, plus the debt service costs of financing the additional borrowing over the projection window. It does not incorporate the administration’s claim that the bill’s pro-growth tax provisions will generate additional revenue; CBO scores policy changes, not behavioral predictions.

What $3.8 trillion in additional debt costs in practical terms depends heavily on the rate at which it is issued. If long-term Treasury yields remain in their current range, the steady-state annual interest cost on that marginal new borrowing, once accumulated over the decade, would approach $175 to $190 billion per year. To put that in proportion: that figure exceeds the combined annual budgets of the Departments of Justice, Homeland Security, Agriculture, and the Interior. It would arrive on top of a baseline interest bill that is already climbing.

The interaction effect matters too. The three major credit agencies downgraded U.S. sovereign debt not because the current deficit is uniquely catastrophic but because the structural trajectory has been consistently one direction. A bill that moves that trajectory further does not operate in isolation from bond market pricing — and the Byrd Rule review will determine how much of the House bill’s deficit impact survives into the Senate version.

The Senate’s Inheritance

The Senate’s procedural calendar for the bill runs through four steps before any final vote is possible: the Parliamentarian’s Byrd bath, Finance Committee markup, floor debate, and a vote-a-rama on dozens of amendments. Each step creates opportunity to modify the bill’s fiscal footprint — though the political pressures are not uniformly in the direction of lower deficits.

Three Republican senators have named their demands publicly. Susan Collins of Maine wants smaller and slower Medicaid cuts. Lisa Murkowski of Alaska wants protections for remote communities and Alaska Native health programs. Josh Hawley of Missouri wants Medicaid work requirements removed entirely, arguing they generate documentation burdens rather than employment gains. Their objections, taken together, push the bill toward spending more rather than less. Senate Majority Leader John Thune of South Dakota holds 53 Republican seats and can absorb three defections. He has no room beyond that.

The Parliamentarian is also expected to examine the bill’s immigration enforcement provisions — detention facility funding, immigration court appropriations, enforcement operations — under the Byrd Rule’s requirement that reconciliation provisions primarily affect federal revenues or outlays, not regulatory policy. If those sections are stripped, the bill the Senate passes will differ from the bill the House passed, and a changed bill must return to the House.

The debt mathematics compounds in the background at every stage. The fiscal year 2024 crossover did not prompt a policy response. The Moody’s downgrade did not alter the procedural calendar. The Fed chair’s warning arrived in a speech and was followed by a committee vote. None of that reversed the trajectory.

What Comes Next

Congress is in recess through Memorial Day weekend. The Senate returns Monday, May 27. Senate Finance Committee Chairman Mike Crapo of Idaho has committed to markup in June. The administration wants Senate passage before the July 4 recess, which requires Finance to finish in early June, floor debate in the second half of the month, and a vote-a-rama before the holiday.

There is essentially no margin in that schedule. A week of stalemate over Collins’s Medicaid objections or Hawley’s work-requirement demands could blow through it. A Byrd Rule ruling that strips broadly supported provisions could force a return trip to the House.

The national debt stood above $36 trillion when Congress returned from its February recess. The interest payments on it — $882 billion in fiscal 2024 — now exceed what the country spent on its military. The question for the Senate Finance Committee in June is whether the provisions worth preserving justify the additional decades of interest the country will pay to carry them.

The monthly Treasury statements will keep arriving regardless of how that question is answered.