What explains President Donald Trump’s foreign policy? Why does his administration bully allies with tariffs and threats of abandonment, and demand better trade balances and more defence spending, yet also cosy up to adversaries including Vladimir Putin and Xi Jinping? Trump’s motivations have been described as mercantilist, isolationist, authoritarian, or even so driven by whim as to be in opposition to US national interests.
Yet such views, which contain elements of truth, miss a deeply rational explanation for some of Trump’s behaviour: an adverse reassessment of the costs and benefits of US grand strategy over the past century, exemplified by liberal global hegemony and offshore balancing. To the degree this reappraisal prevails in Washington, it has profound consequences for America’s allies, not least Australia.
As background, a key goal of US grand strategy to date has been to prevent any other state seizing the world’s centres of power beyond Washington’s backyard: principally Europe, Asia, and the Middle East. A dominant power in one or more such areas could eventually marshal the resources to threaten America itself.
A common method sought to forestall this problem: working with local states to help them balance power against the rise of a regional hegemon. This was vastly cheaper in blood and treasure than the US seizing an overseas outpost.
Differences came about in securing local cooperation. Under global hegemony (America’s approach after the Cold War), Washington maintained a large overseas presence of bases and alliances, intervening promptly to extinguish security brushfires while also building cooperation against strategic threats. Under offshore balancing (the principal approach before 1945), US forces mainly stayed home, intervening only when immediately necessary (such as both World Wars) or in an enduring way during the Cold War due to the constant Soviet threat.
Regardless of the approach, the United States often encouraged dependency among its allies, notably in nuclear weapons but also in key military enablers such as communications and intelligence. Such states thus remained pliable (many supported Washington’s wars in Iraq and Afghanistan) and unable to threaten America. In turn, those nations benefitted by being able to pay less for their own defence.
China’s military power is enormous and growing, requiring increasing US investment to balance while lacking a NATO equivalent to efficiently shoulder more of the burden. So why not reach a grand bargain with Beijing, as Trump appears to want?
The broad continuity of the US approach for more than 100 years dulled concerns that America’s calculus might change. Yet there were warnings that Washington would grow tired of footing the bill for global hegemony. Further, being safely behind an ocean, it might well decline even offshore balancing if the costs appeared inordinate, instead accepting local hegemons – not least if it could still trade with their regions.
It seems Trump has made just such calculations, as this explains many of his foreign policy behaviours. Note the president’s references to the “big, beautiful ocean” the United States is safe behind and Secretary of State Marco Rubio’s comments on a return to a multipolar world order. Consider the plan to redirect vast sums mostly away from conventional military forces into other capabilities including the Golden Dome homeland missile shield, which would inoculate America against the one danger that can reach across the seas.
Seeking wealth while ditching balancing also explains Trump in Europe and Asia. The demands for additional defence spending, and better market access, serve to defray US costs while keeping America affluent via trade, the latter achieved through threats to allies and pleasantries to potential hegemons.
Further, there’s no reasonable chance of one country conquering Europe: the local states are too fractured, and Russia too feeble. So why retain a presence there? The Asia-Pacific represents the reverse challenge: China’s military power is enormous and growing, requiring increasing US investment to balance while lacking a NATO equivalent to efficiently shoulder more of the burden. So why not reach a grand bargain with Beijing, as Trump appears to want? Perhaps guaranteeing access to the region’s markets in return for the United States withdrawing behind its dome?
Trump’s likely recalculation means three key things for US allies.
First, the old days are gone. While hegemony and offshore balancing made rational sense – hence some politicians’ shock about the sudden lack of US concern for their regions – America’s grand strategy has probably turned. And not just for Trump; there’s every chance Washington in general will come to similar conclusions.
Second, more defence spending is needed to counteract a US retrenchment, including by helping change America’s calculus to keep it involved. Yet (paradoxically) doing so may also drive it away. After all, the more potent are the regional actors arranged against Moscow and Beijing, the more safely can Washington stay abroad.
Third, it’s wise to reduce dependence on America wherever possible, but do so astutely – particularly under today’s mercurial president. For Canberra, there have already been calls for new foreign and defence policy options. Another logical path is to accelerate purchases (and onshoring production in Australia) of US weapons that can be procured promptly, with much money and fanfare for Trump. But costly, long‑term cooperative programs such as the nuclear-powered submarine acquisition should be voided and avoided – as these may be axed on a whim, a change of government in Washington, or the altar of a grand bargain with Xi.
There’s much to be done, and quickly.