Washington ran a $2.0 trillion deficit in fiscal 2026, according to the Congressional Budget Office. Federal spending reached about $7.4 trillion, and revenue came in at about $5.4 trillion.
So when does government debt become dangerous?
Three Numbers That Get Confused
A deficit is the amount by which government spending exceeds revenue in a given year.
Debt is the accumulated borrowing that results from years of deficits.
Gross domestic product (GDP) measures the value of goods and services the economy produces in a year.
The debt-to-GDP ratio compares what the government owes with a year's economic output. But that ratio alone cannot tell us whether the debt is sustainable.
Size Alone Isn't the Test
Debt sustainability depends on three things: the interest rate the government pays, economic growth, and the primary balance, which is revenue minus spending before interest costs.
If the economy grows faster than the interest rate on its debt, a large debt burden becomes easier to manage. If interest costs grow faster than the economy, stabilizing the debt generally requires a stronger primary balance.
Japan shows that the percentage alone doesn't decide the outcome. The International Monetary Fund projects Japan's gross government debt at roughly 200 percent of GDP in 2026. Japan has carried that burden for years without a sovereign debt crisis. Its measure is gross general-government debt, which is not directly comparable with the U.S. figure below.
The IMF's warning is about the path, not the level. It expects rising interest costs and an aging population to push Japan's debt ratio up from 2035 unless the government keeps its finances disciplined.
Borrowing That Builds Versus Borrowing That Covers
Think of a credit card. Borrowing for a laptop that raises your earnings can pay for itself. Borrowing repeatedly to cover existing interest charges leaves you owing more without improving your ability to repay.
Government faces the same distinction. Borrowing for infrastructure, research or emergencies can generate lasting benefits. Borrowing to finance recurring deficits and rising interest costs makes the debt harder to manage over time. Even useful public projects should be weighed against their full costs and the alternative uses of the money.
Where America Stands
CBO's September review estimates publicly held debt at about 100 percent of GDP at the end of fiscal 2026. Its February baseline projects 120 percent by 2036. Net interest is projected to grow from about $1 trillion this year to $2.1 trillion in 2036. Interest is already the second-largest federal expenditure, behind only Social Security, and CBO expects it to exceed defense spending in every year of its outlook.
Those costs reach ordinary people. Imagine a town whose residents save $100 in total. This is a simplified picture: "savings" here means resources people set aside rather than spend, not the money in circulation. If the town borrows $60 for roads, only $40 remains for the bakery, the farm and the machine shop. If the bakery wants a $30 loan for a new oven, lenders may charge more, and the bakery may skip the oven. A farmer named Maria with a $50,000 tractor loan may find the payments work at 4 percent interest but not at 6 percent, so she keeps her old tractor.
These examples illustrate the mechanism; they are not data. The core idea is that heavy government borrowing can push up interest rates and crowd out some private investment. CBO has described this effect: larger federal debt can crowd out private investment and reduce output over time. The effect is neither automatic nor dollar-for-dollar, and its size depends on economic conditions.
The Real Danger
Debt becomes dangerous not simply when it crosses a particular percentage of GDP, but when deficits, interest costs and weak growth keep pushing the debt burden higher. Borrowing for productive investment can make economic sense. Persistent borrowing without a credible path to stability creates growing risk.
The essential question is not whether America has crossed 100 percent of GDP. It is whether the country can stabilize its debt while still investing in the productivity that sustains prosperity. Under current law, CBO projects the debt ratio will keep rising.
On October 21, Dr. Carolyn Bourdeaux joins us for a Chart Talk on America's fiscal outlook and the choices ahead.
Earlier in This Series
Can America Grow Its Way Out of the Debt Problem?
Why Does Washington Keep Borrowing?
Sources
Congressional Budget Office — Monthly Budget Review, September 2026 (fiscal-year summary via American Action Forum, October 8, 2026)
americanactionforum.org →
Congressional Budget Office — Monthly Budget Review: August 2026
cbo.gov →
Congressional Budget Office — Testimony on The Budget and Economic Outlook: 2026 to 2036, March 11, 2026
cbo.gov →
International Monetary Fund — IMF Executive Board Concludes 2026 Article IV Consultation with Japan, April 2026
imf.org →
Congressional Budget Office — Budgetary and Economic Outcomes Under Paths for Federal Revenues and Noninterest Spending, March 2016 (on crowding out)
cbo.gov →