Barack Obama spent his first term undoing what he saw as the excesses of U.S. post-Cold War foreign policy, from land wars in the Middle East to insufficient attention to Asia. By his own account, he largely succeeded. But chances are he will spend his second term grappling with the flaws in his cure. Contrary to the usual Republican narrative, Obama did not lead a U.S. retreat from the world. Instead he sought to pursue the same interests without the same means. He has tried to preserve America’s place as the “indispensable nation” while withdrawing ground troops from war zones,...