The Impact of Increasing National Debt

What is the Trend for the National Debt?

When the federal budget is higher than tax revenue received in a given year, the federal government has a budget deficit and the Treasury Department issues bonds to make up the difference. Investors—people, other governments, and financial companies—buy these bonds because they offer a fixed and guaranteed interest rate (typically in the 2-5% range). These bonds cover the difference in spending vs. tax revenue, but lead to an increase in the national debt, which is the sum of every year’s deficit plus the interest owed on the money borrowed.

The standard way to measure the size of the national debt is as a percentage of Gross Domestic Product (GDP), the amount of goods and services produced by the U.S. economy. After an increase during World War II, the national debt was about 40% of GDP until about 1980. Since then, however, the debt has steadily increased, exceeding 100% of GDP in recent years, as shown in the figure below.

The 100% debt to GDP level is seen by some economists as the point where the national debt should begin to have significant negative effects. However, despite the national debt being over this level since 2010 or so, these effects have not been observed. Except for a brief spike in inflation and interest rates caused by supply chain disruptions during the COVID pandemic (see our Inflation brief for details), Americans have generally enjoyed low unemployment, moderate economic growth, and a rising stock market.

Moreover, as the figure below shows, the increasing debt has not affected the distribution of federal spending. The figure aggregates spending into four categories: entitlements (Social Security, Medicare, Medicaid, etc.), defense, interest payments on the debt, and everything else. For details on each type of spending, see our policy briefs on federal spending.

The figure shows that the percentages of GDP spent on each category are roughly the same over time. There are two exceptions: (1) a spike in spending on non-defense, non-entitlement programs in 2020-21 due to COVID assistance programs and (2) a slight increase in interest payments beginning in 2021, due to the higher interest rates on government bonds used to finance the deficit.

Why The Debt Matters

The stability in federal spending levels is about to change. The chart below shows the predicted change in actual spending in 2023 versus projected spending for 2029 – five years from now.

Over the next five years, interest payments will increase almost 30 percent due to the increased size of the national debt and the higher expected interest rates that will be paid on government bonds. The chart shows how this increase will affect spending on other non-interest payment categories if no significant changes are made to policies regarding taxing and spending. The likely outcome - Defense spending will increase by only 1 percent. Entitlement spending will decline by almost 10 percent. And spending on all other government programs will decrease by over 30 percent.

The Take-Away

While the increasing national debt has not yet damaged the American economy, it is about to have a serious impact on federal spending. As debt payments increase, spending on all other programs will be crowded out. With the exception of defense spending, every other federal program will see spending cuts, in most cases at a severe level.

Cutting the national debt will require painful choices to raise taxes and / or cut spending, requiring a debate over what the government should and should not do. Our brief shows that if these choices are not made, increasing debt payments will constrain virtually every non-defense federal program, without regard to the priorities held by the American public.