Discretionary Spending
Discretionary spending is usually broken into two categories: defense spending and non-defense spending.
- Defense spending is spending on the military and includes things like payroll for military personnel, weapons, and maintenance on equipment. Defense spending is the largest component of discretionary spending, but it has been declining as a share of government spending over the past 50 years. In 1962, defense spending was 50% of the entire federal budget and 70% of discretionary spending. In 2019 it had fallen to 15% of the entire budget and 50% of discretionary spending. Another way to think about the amount of defense spending is as a proportion of GDP. Defense spending has fallen from 9% of GDP to just over 3% of GDP since 1962.
- Non-Defense spending includes things like education, NASA, low-income housing provided by the Department of Housing and Urban Development, etc. Unlike defense spending, non-defense spending has been remarkably constant. It has made up between 15-25% of the total budget and about 4% of GDP since the 1960s.
Figure 1: Defense Spending as a Percentage of GDP

Source: Congressional Budget Office.
Figure 2: Non-Defense Discretionary Spending as a Percentage of GDP

Source: Congressional Budget Office.
Discretionary Spending has been shrinking as a percentage of government spending and as a percentage of GDP. In 1962 it was two-thirds of all federal spending, and in 2019 it was less than one-third. In that same time, it fell from over 12% of GDP to just over 6%.
Figure 3: The Changing Distribution of Federal Spending

Source: Congressional Budget Office
Figure 4: Discretionary Spending as a Percentage of GDP

Source: Congressional Budget Office.
Mandatory Spending
Mandatory spending is spending required by past commitments made by the government. Most mandatory spending is on programs referred to as entitlement programs because people have paid into the programs with the expectation that they would receive benefits at a later date. Medicare, Social Security, and federal pensions are examples of entitlement programs. Mandatory does not mean unchangeable, but it does mean that change has to come about by changing the laws that dictate the spending.
Mandatory spending accounts for two-thirds of the federal budget, and it has increased from 4.8% of GDP in 1962 to 12.9% of GDP in 2019.
Figure 5: Mandatory Spending as a Percentage of GDP

Source: Congressional Budget Office.
The growth in mandatory spending is driven by the three largest categories of mandatory spending: Social Security (24% of the overall budget), Medicare (14% of the overall budget), and Medicaid (9% of the overall budget).
- Social Security is the Old Age, Survivors And Disability Insurance Program (OASDI), and it is run by the U.S. federal government. It provides retirement benefits, survivor benefits, and disability income. Between 1962 and 2019, Social Security spending grew from 2.4% to 4.9% of GDP (Figure 6). The main contributor to this growth is that there are more retirees now than ever before. People are living longer than they were back in 1962, but the retirement age to claim Social Security has not changed enough to keep pace. Between 1962 and 2019, life expectancy in the United States increased by 7 years. However, the age of retirement for Social Security has only increased from 65 to 67. Therefore, people are living an additional 5 years on Social Security, which has increased the amount of spending on the program. In addition to people living longer, the baby boomers are starting to retire. As this large segment of the population moves into retirement, it will lead to an additional strain on the Social Security system. In 2019, Social Security outlays were $1,038 billion; they are expected to increase to $1,926 billion by 2030. That is the annual rate of increase of almost 6%, which is much faster than the expected growth of GDP over the same period of time (Posmanick and Baier).
Figure 6: Social Security Spending as a Percentage of GDP

Source: Congressional Budget Office.
- Medicare is the federal health insurance program for people who are 65 or older and younger people with certain health conditions like ALS, kidney failure, and COVID-19 (US Centers for Medicare & Medicaid Services). Medicare spending did not begin until 1967, but expenditures on Medicare have seen an increase from effectively 0% of GDP in 1962 to 3.7% of GDP in 2019 (Figure 7). Medicare has expanded as rapidly as it has for many of the same reasons that Social Security spending has—namely, the aging of the population. However, Medicare spending has increased faster than Social Security because Medicare spending increases not only with the age of citizens but also with the price of medical services. As medical costs have increased over the last 50 years, so has the percentage of GDP needed to provide Medicare (Posmanick and Baier).
Figure 7: Medicare Spending as a Percentage of GDP

Source: Congressional Budget Office.
- Medicaid is similar to Medicare, but instead of acting as insurance for older Americans, Medicaid acts as health insurance for poor Americans. Medicaid spending has increased from 0% of GDP in 1962 to 1.9% of GDP in 2019. The increase was particularly pronounced during the early 90s, during the great recession, and with the passage of the Affordable Care Act and subsequent Medicaid expansion in 2010. But unlike the other components of mandatory spending, it is somewhat cyclical. The reason for this is straightforward: when the economy goes into a recession, more people will qualify for and receive payment from Medicaid, and when the economy is expanding, fewer people will be eligible for Medicaid, and more periodic payments are likely to go out.
Figure 8: Medicaid Spending as a Percentage of GDP

Source: Congressional Budget Office.
- Interest Payments on the debt are another type of mandatory spending. They make up 8% of the overall budget. While the interest payments are not determined by legislation, they are payments the government committed to when they borrowed the money. They are payments to bondholders or those who lent the government money by buying bonds. This includes individuals, corporations, state or local governments, the Federal Reserve Banks, foreign governments, and entities outside the U.S. Interest payments as a percentage of GDP have not changed much since 1962, but they have ranged from 1.2% to over 3% (Figure 9). Two things can cause a growth in interest payments: higher interest rates and higher levels of debt. While interest rates have actually been decreasing, the level of federal debt has been increasing, and both of these will influence future interest rates.
Figure 9: Net Interest Expenditures as a Percentage of GDP

Source: Congressional Budget Office.
- Other mandatory spending includes pensions for federal employees, veterans’ benefits, and income security, but these categories are relatively small compared to Medicare, Medicaid, and Social Security.…)
Looking forward, the Congressional Budget Office projects that federal spending as a percentage of GDP will continue to grow. Discretionary spending will continue to decline as a percentage of GDP, and mandatory spending will continue to rise.
Figure 10: Projected Federal Spending as a Percentage of GDP

Source: Congressional Budget Office.
Figure 11: Projected Mandatory Spending as a Percentage of GDP

Source: Congressional Budget Office.
Figure 12: Projected Discretionary Spending as a Percentage of GDP

Source: Congressional Budget Office.
Sources
Capretta, James C. “Fiscal Policy and the Major Entitlements: An Introduction.” Foundation for Teaching Economics, 2020, www.fte.org.
Posmanick, and Scott Baier. “Federal Debts and Deficits: Past, Present and Future.” Foundation for Teaching Economics, 2020, www.fte.org.
US Centers for Medicare & Medicaid Services. “What’s Medicare?” Medicare.Gov, Centers for Medicare & Medicaid Services., https://www.medicare.gov/what-medicare-covers/your-medicare-coverage-choices/whats-medicare. Accessed 20 10 2020.