Is a high defense budget in US interests? National defense spending has reached about $500 billion per year, representing about one half of world military spending. This policy has allowed the US to build up unparalleled military strength, but the consequences on long term US interests are not questionable.
Following World War II Western strategists tried to fashion a global security strategy based on free trade and cooperation. In order to work, this strategy required US leadership to protect smaller states and enforce international standards. At the time, US policy makers perceived this to be consisted with US national interests. But what behaviors has this mega-role produced in US allies?
In terms of defense, US worldwide strategic partners have increasingly become free-riders. The US defense budget is roughly 4% of GDP. Contrast this with budgets of major US allies: defense spending in Canada is about 1% of GDP, in France 2.6%, in the UK 2.4%, in Germany 1.5%, and 1% in Japan. The comparative magnitude of US GDP widens these discrepancies.
One may argue that these budgets simply reflect a post-World War II proclivity in the US for military enlargement, while its allies perceive threats more realistically. A counter to this argument is China, a country which has pursued double-digit growth in its defense budget for the past several years on end. China spends around 4.3% of its GDP on defense—a higher percentage than the US—and in purchasing power parity dollars, Chinese GDP is close to 75% of US GDP. Even when allowance is made for the irrelevance of purchasing power parity analysis for some types of military goods, this is still a formidable development. The charge that Washington is hyper-sensitivity to security threats does not sufficiently explain the budget gaps.
International security is by nature a public good—many entities benefit from it, few are keen to produce it. The US has been the sine quo non Western security provider since World War II, as is reflected in defense budget comparisons with its allies. It is time for them to assume a larger role in international security.