With his Syria policy careening from inaction to the threat of force to a request for congressional approval to a diplomatic bailout from Russia, the long-vexing puzzle of what makes Barack Obama tick has again come to the fore.

About most presidents, it’s possible to put together a sentence or two that plausibly describes their view of the world and where they sought to take the country. Reagan wanted to rebuild American strength and unleash economic growth at home. The Cold War over, George H. W. Bush, himself no ideologue, was pragmatically looking to shape a “new world order.” Bill Clinton was a “New Democrat” who sought a third way between the old-school liberalism of a Ted Kennedy and the surge of ideological conservatism that nearly engulfed him. George W. Bush found his purpose after 9/11, which was to wage a “global war on terror.”