Defense spending accounts for about half of discretionary spending by the U.S. government. Other discretionary spending includes expenditures on education, public health, infrastructure, scientific research and energy. In the fiscal year ending Sept. 30, 2019, total discretionary spending of $1.3 trillion was 30% of the total budget of $4.4 trillion.
In the current fiscal year, defense spending is more than half of requested discretionary spending.
Non-discretionary (mandatory) spending must be funded by Congress under federal law. It includes programs such as Social Security, Medicare, Medicaid and unemployment insurance.
Discretionary spending is determined by Congress each year. In 2019, at 3.1% of national output, it reached the lowest level since 1962. Spending to offset the impact of the coronavirus pandemic is likely to reverse the downward trend over the next few years.