Great sea changes of foreign policy thought are rare in American public life. But there’s abundant evidence that the US is experiencing one now.

Polls show that the American people are tired of the world, with a majority believing that it’s high time for the nation to concentrate on its own neglected internal problems. The defense budget has fallen and will continue to fall, and there’s a strong aversion to seeing US soldiers killed and wounded. To the extent that such views prevail, they’re inimical to the post-Cold War consensus that the US should impose its will and leadership across the globe.

Enter Donald Trump, whose divisive rhetoric and rude-and-crude behavior shouldn’t disguise the fact that he has caught the significance of the new mood. Like Bernie Sanders, Trump found a receptive primary campaign audience whenever he questioned America’s propensity for promoting democracy and subsidizing allies’ defenses. And, unlike Hillary Clinton, he recognizes that US military interventions in the Middle East all too often make a bad situation worse, getting America bogged down in sectarian wars while radicalizing a new generation of jihadist.

If a foreign policy keeps hurting US interests and making the world a far more dangerous place, then some new thinking is in order. Unfortunately, Trump’s failed to match his shrewd instincts with any policy substance. He could do worse than consult an important article in the latest Foreign Affairs magazine.

John Mearsheimer from the University of Chicago and Stephen Walt from Harvard University are two of America’s most distinguished scholars of international relations. Neither will vote for Trump or work for his administration if he’s elected in November.

Nonetheless, they agree with Trump in his rejection of idealistic crusades. As the US interventions in Afghanistan, Iraq and Libya have shown, there’s not an American solution to every problem. In fact, there are a good many problems, for which there may be no solution at all. They also agree that “free riders”—allies whose security relies overwhelmingly on US largesse—are a consequence of the post-Cold War strategy of global liberal hegemony.

Mearsheimer and Walt instead propose a policy of offshore balancing, which concentrates on preserving US hegemony in the Western Hemisphere and preventing the rise of hegemonic powers in Europe, Asia and the Persian Gulf.

In deciding when to deploy military power, they argue, the US should allow problems to be handed to those closest to the problem. This way, a sense of responsibility and initiative can be developed throughout the international system and the US can reserve its own intervention for the great issues, acting as a balancer of last resort rather than what Madeleine Albright called an ‘indispensable nation’.

In practice, that means that the US should get out of Europe and turn NATO over to the Europeans, as Trump himself suggests. Russia, after all, is a declining power, whose actions in the Baltics are more reactive to western policy (NATO expansion, for instance) than aggressive.

In the Persian Gulf, the US should aim to prevent Iran, the only rising power in the region, from becoming a hegemon via a limited rapprochement. (Egypt, Syria, Israel aren’t vital strategic interests.) Meanwhile, acting as a balancer of last resort in the Middle East would ameliorate America’s terrorism problem. Why? Because such a policy respects the sovereignty of other states and doesn’t trigger nationalist anger at the US, which is one of the main driving forces behind jihadism.

Asia’s different. The rise of China, Mearsheimer and Walt suggest, is bound to threaten the regional equilibrium, so US military force will be needed in the region more than ever. That’s especially so, given that US allies are unable or unwilling to balance Beijing’s hegemonic ambitions on their own.

None of this means abandoning America’s position as the world’s greatest power or retreating to a form of isolationism. It means that although the US can afford to scale back somewhat and force other states to bear a fairer share of global burdens, Washington will need to remain the balancer of last resort in those strategically important regions. By being more discriminating, selective and prudent, a policy of offshore balancing will prevent rivals from dominating key regions of the world and preserve US primacy over the long haul.

Trump should embrace the Mearsheimer–Walt thesis, which would be manna from heaven.

This piece first appeared in ASPI's The Strategist here. 

Image: Flickr/Creative Commons.