Defense spending accounts for roughly half of the portion of the budget referred to as discretionary spending, which is determined through the annual appropriations process. Recent war spending is included in this total, although that spending has primarily been approved through supplemental bills, instead of through regular apprioriations.

Defense spending is now substatially lower, as a share of the economy, than it was during the Cold War, but higher than it was during the late 1990s when the "peace dividend" helped contribute to budget surpluses. Going forward, it is important that the defense budget be held to similar scrutiny as non-defense spending. However, future deficit projections already assume defense spending will decrease, meaning our fiscal challenge cannot be solved by cutting defense spending alone.