Discretionary Spending

Function 050 - National Defense

Reduce the Department of Defense’s Budget

CBO periodically issues a compendium of policy options (called Options for Reducing the Deficit) covering a broad range of issues, as well as separate reports that include options for changing federal tax and spending policies in particular areas. This option appears in one of those publications. The options are derived from many sources and reflect a range of possibilities. For each option, CBO presents an estimate of its effects on the budget but makes no recommendations. Inclusion or exclusion of any particular option does not imply an endorsement or rejection by CBO.

Billions of Dollars 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2019-
  Reduce DoD's Budget by 10 Percent Relative to the Amount Planned for 2022
Change in Planned Defense Spending  
  Budget authority 0 -23 -46 -71 -65 -68 -73 -75 -84 -87 -204 -591
  Outlays 0 -13 -32 -53 -58 -63 -68 -71 -77 -82 -156 -517
  Reduce DoD's Budget by 5 Percent Relative to the Amount Planned for 2022
Change in Planned Defense Spending  
  Budget authority 0 -11 -23 -35 -28 -31 -35 -35 -43 -44 -98 -284
  Outlays 0 -6 -16 -26 -27 -28 -32 -33 -38 -41 -76 -248

This option would take effect in October 2019.
Estimates of savings displayed in the table are based on the 2019 Future Years Defense Program and the Congressional Budget Office's extension of that plan.
DoD = Department of Defense.


The Department of Defense (DoD) received $616 billion in appropriations for its base budget in 2019, the highest amount since 2010 (after adjusting for inflation). The Department's Future Years Defense Plan (FYDP) for 2019 anticipates that base-budget levels will average about $650 billion per year (in 2019 dollars) through 2023. (DoD's base budget is intended to fund enduring activities, such as day-to-day military and civilian operations and development and procurement of weapon systems. It does not include additional funding appropriated for nonpermanent activities, such as overseas contingency operations or other emergencies.) Before 2019, the amount appropriated in 2010 had been the highest for DoD's base budget, which had grown by 50 percent since 2000, and surpassed even the 1985 budget, DoD's largest peacetime budget during the Cold War. After 2012, DoD's base budgets decreased under the constraints of the Budget Control Act of 2011 (BCA), averaging about $550 billion for 2013 through 2018.


This option encompasses two alternative decreases in DoD's budget. The first would reduce DoD's budget over three years so that funding in 2022 would be 10 percent less than the funding planned for that year in the Administration's 2019 FYDP. The second would reduce DoD's budget by 5 percent over that same period. Both alternatives would allow for real (inflation-adjusted) growth of 1 percent annually after 2022.

Effects on the Budget

Under the first alternative, funding for DoD in 2022 would be $637 billion, excluding funding for overseas contingency operations. That amount would still be large by historical standards; adjusted for inflation, it would be roughly in line with DoD's base budget in 2012, the last budget prepared before the BCA's caps were applied, and more than Cold War spending at its height. Through 2028, cumulative funding for DoD would be reduced by $591 billion under the first alternative. That estimate of savings is based on the costs of plans outlined in the 2019 FYDP (which defines plans and costs through 2023) and the Congressional Budget Office's projections of costs over the following five years. Under the second alternative, savings would total $284 billion through 2028.

Savings would be smaller if DoD needed more than three years to implement the reductions under this option or if the costs of current plans were overstated. Conversely, savings could be larger if costs to implement current plans were underestimated. For example, DoD has frequently underestimated its costs to develop and purchase weapon systems.

Other Effects

Accommodating the smaller amount of funding under this option would require DoD to decrease the size of its forces, slow the rate at which it modernizes weapon systems, or do both. Force cuts could be made proportionally across the services or could be tailored to the specific needs of parts of the military. Similarly, to achieve a desired pace of modernization, DoD would need to balance the goal of maintaining a particular force size against the goal of procuring new weapons. (CBO's estimate of savings in outlays is based on proportional reductions to each part of DoD's budget.)

With a somewhat smaller force, DoD's ability to execute all the elements in the current national security strategy would be lessened. The current strategy envisions prevailing at both the low end of the spectrum of conflict (for example, counterinsurgency operations) and at the high end (conflicts with Russia or China). Simultaneously pursuing those goals is expensive. For example, at the same time that the Army has soldiers in more than 140 countries, all four military services are buying highly sophisticated military weaponry to fight against Russia or China, and DoD is modernizing all elements of its nuclear forces. Under this option, DoD would need to focus its efforts on the most important elements of national security, cut back in some other areas, and rely more on both conventional and nuclear deterrence to dissuade Russia and China from attacks on the United States, its interests, or its allies. For instance, DoD might need to scale back or eliminate the Army's presence in some countries and replace that military effort with other instruments of national power. Such a shift from military to nonmilitary engagement would not be inconsistent with the Summary of the 2018 National Defense Strategy of the United States of America, which calls for "the seamless integration of multiple elements of national power—diplomacy, information, economics, finance, intelligence, law enforcement, and military." The reduced size of the military and concurrent shift to a more integrated approach would require greater patience in addressing crises around the world, however: Diplomacy rarely offers the dramatic action (or speed) of military intervention.

One argument against this option is that the size and number of military operations that could be conducted simultaneously and the duration for which they could be sustained would be diminished. Under Army policy, for example, three active brigade combat teams (BCTs) are required to support the rotation of a single BCT in and out of a combat zone. Consequently, the number of BCTs that the Army could continuously deploy would decrease by one for every three active BCTs that were cut from the force structure. Similar considerations would apply to the deployment of naval and air forces. If the need for a large, sustained military presence overseas arose, DoD could increase the size of its forces at that time (as it has done often in the past), but it could take a few years.

Despite the reduced military capacity under this option, the United States would remain the world's preeminent military power. Even in 2022, when funding would be lowest under this option in both nominal and inflation-adjusted terms, it would be nearly double the combined military spending of China and Russia in 2017.