Geopolitical

America's Global Military Posture

37%of GDP

At the height of WWII, national defense consumed nearly two-fifths of the entire U.S. economy. Today it runs around 3%.

Defense ate nearly 40% of the entire economy at the height of WWII. The peacetime baseline it settled into reshaped the world. The U.S. still spends more than the next several countries combined and maintains commitments from NATO to the Indo-Pacific — credited with underwriting global stability and criticized as overextension in roughly equal measure. Here's where the money goes, how the spending arc evolved since 1940, where U.S. forces are, how aid to partners actually flows, and why "spend more" and "spend less" both command real coalitions.

Defense, share of GDP

~38%

WWII peak (1944) vs ~3% today — OMB

U.S. defense budget

$850B

FY2025 DoD enacted; ~$895B national-defense topline

Share of world military spending

37%

$997B of $2,718B world total — SIPRI 2024

Troops stationed abroad

~173K

across ~750 base sites in 80 countries

Aid to Ukraine since 2022

$174B

appropriated FY22–24 (CRS); ~$127B allocated (Kiel)

The topline

The U.S. enacted roughly $841 billion in discretionary funding for the Department of Defense in fiscal year 2025 — and about $895 billion for "national defense" once you add the Energy Department's nuclear-weapons work and other defense activities. That single year exceeds the entire economies of most countries. But the budget is less about hardware than most people assume: the two biggest slices are the cost of running the force — operations, maintenance, and the people who serve — not buying new weapons.

FY2025 enacted DoD budget · by appropriation title$ billions

Operation & Maintenance$290.3B

Readiness, training, fuel, base operations, civilian payroll, depot maintenance. The single largest slice — the cost of running the force day to day.

Military Personnel$182.4B

Pay, allowances, and benefits for ~1.3M active-duty and 0.77M reserve service members.

Procurement$167.5B

Buying the hardware: aircraft, ships, ground vehicles, missiles, munitions.

RDT&E$141.2B

Research, development, test & evaluation — next-generation weapons, from hypersonics to AI-enabled systems.

Other$59.9B

Military construction, family housing, revolving & working-capital funds, and defense-wide accounts.

Total (DoD discretionary, 051)$841.3B

Source: CRS, "FY2025 Defense Appropriations: Summary of Funding" (P.L. 119-4). "Other" includes military construction, family housing, and revolving funds.

It's mostly people and upkeep

Operation & maintenance plus military personnel — together more than half the budget — are the recurring cost of a standing, globally deployed force. Cut procurement to zero and you'd still spend most of the budget keeping the existing force ready.

Procurement vs. R&D

About $310B goes to acquisition — $167B buying today's weapons and $141B developing tomorrow's. The R&D share has risen as the Pentagon races China on hypersonics, autonomy, and AI-enabled systems.

What the topline leaves out

Veterans' care (a separate ~$350B department), interest on war debt, and intelligence spending sit outside the DoD line. Brown University estimates the post-9/11 wars alone will total ~$8 trillion all-in.