Defence — United States · Synthesis

The world's largest military budget, by a very wide margin. US military spending is in the region of 900 to 970 billion dollars (SIPRI / DoD budget), or around 3.4% of GDP and on the order of 37-40% of world military spending. This budget alone exceeds the combined budgets of the leading next powers — a dominance without equivalent.

A global force. The armed forces number on the order of 1.3 million active-duty personnel (DoD), supplemented by the reserve and the National Guard. The United States maintains a network of bases abroad without equivalent (hundreds of installations across every continent), a leading navy and air force, and worldwide power projection.

The foremost Western nuclear deterrent. The United States holds, along with Russia, one of the two largest nuclear arsenals (several thousand warheads), with a full triad (submarines, intercontinental missiles, bombers) undergoing modernization — a very long-term and very costly programme.

The leading arms exporter. The United States is the world's leading arms exporter (≈ 40% of the market, SIPRI), far ahead of the others. Its sales shape the arsenals of many allies (Europe, the Gulf, Asia), strengthening both its industry and its strategic influence.

An industrial base under strain. Despite its size, the defence industrial base is the subject of warnings (munitions production capacity, lead times, dependence on certain inputs) revealed by support for Ukraine and the prospect of a high-intensity conflict — a recurring topic of CRS and GAO reports.

Strategic competition with China. The Chinese "pacing challenge" shapes defence strategy: a pivot to the Indo-Pacific, deterrence in the Taiwan Strait, a race for technologies (hypersonics, AI, space, cyber). It is the central determinant of the outlook.

Cost and the budget debate. The defence budget, already very high, fits within a context of record deficit and debt (cf. Economy category). Its evolution, equipment priorities and nuclear modernization are the subject of trade-offs in Congress, between security pressure and fiscal constraint.

Support to allies and burden-sharing. Support for Ukraine, the commitment to NATO and the demand placed on allies to increase their spending (cf. Defence France note) are redrawing the transatlantic balance. The degree of US commitment is a recurring topic of internal debate.

Innovation and industry. Closing the weaknesses of the industrial base (munitions, ships, drones), integrating disruptive technologies and accelerating procurement ("defense acquisition" reform) are priority undertakings identified by the DoD and Congress.

The open questions. Three trade-offs will shape the period: (1) maintaining the lead in the face of China's military rise; (2) funding an already colossal effort within a constrained fiscal framework; (3) repairing the industrial base to sustain a protracted conflict.

Placed in their environment, the United States is the world's foremost military power with no close rival in volume, even though China is narrowing the capability gap in certain regional domains.

Three takeaways. (1) A unique budgetary dominance. At ≈ 900-970 bn$, the US budget is about three times that of China (≈ 300-340 bn$) and more than ten times that of France, Germany or the United Kingdom (≈ 60-100 bn$ each).

(2) China, a rising challenge. China is the second-largest budget in the world and is rising fast, particularly in its own zone (navy, missiles, A2/AD). The overall gap remains wide, but it is narrowing in the Indo-Pacific — the central issue of US strategy.

(3) A pivot role for allies. As the leading exporter and pillar of NATO, the United States shapes the defence of its allies. Its level of commitment conditions the European rearmament effort (cf. Defence France note).