The clearest expression of a foreign policy doctrine President Obama has articulated came in 2012 when he announced that the “tide of war in Afghanistan” had “turned” and that this was lucky because it was “time to focus on nation building here at home.” Al Qaeda, defined so narrowly as to exclude everyone save Osama bin Laden and his closest friends, was declared “defeated,” and a satisfied commander in chief confidently turned to domestic matters.

Obama’s assumption that a vigorous foreign policy and a successful domestic agenda are in conflict is wrong. The U.S. experienced high rates of economic growth and development (with occasional recessions) throughout the post-World War II period while also maintaining the world’s largest military. In the 19th century, Britain’s citizens enjoyed among the best living standards in the world even as the nation maintained an empire and ensured freedom of navigation for all. Though many Americans now recoil from the role for themselves, the British served for most of the 19th century as the “world’s policeman.”