Yet, according to an increasingly influential chorus of foreign relations scholars and historians such as Andrew J. Bacevich, Barry Posen, and Stephen Walt, the fundamental problem lies not in the military itself, but in the realm of American politics and grand strategy. One administration after another has engaged in imperial overreach, trying to reshape societies and entire regions of the world about which, despite the vast intelligence assets they command, they remain fundamentally ignorant.

After the catastrophe in Vietnam, the military and the foreign policy establishment were determined to stay clear of foreign entanglements where America’s vital interests were not clearly at stake. According to the Weinberger Doctrine—named for Ronald Reagan’s secretary of state, Caspar Weinberger—the U.S. military should only be deployed when policymakers could define clear and attainable objectives, and only as a last resort.

As these scholars see it, the Weinberger doctrine went into sharp decline after the Gulf War and vanished into thin air with the arrival of the global War on Terror. Since the early ’90s, one president after another, Republican and Democrat, has pursued an overly militarized foreign policy agenda, deploying forces instead of seeking solutions through the country’s other instruments of influence: diplomacy, soft power, and economic incentives.