[Yoni Appelbaum is a social and cultural historian of the United States. He is a doctoral candidate at Brandeis University, and a lecturer in history at Babson College. He previously contributed to TheAtlantic.com under the name Cynic.]

President Obama's pragmatic approach to foreign policy has long frustrated observers. His decisions -- drawing down forces in Iraq while surging troops into Afghanistan, leaving the Fifth Fleet docked in Bahrain while the Sixth Fleet pummels Libya -- have laid him bare to charges of inconsistency and incoherence.

A Politico headline sums up the common complaint: "In Search of the 'Obama Doctrine." "I certainly don't see any Obama doctrine," sniped Max Boot. "Instead what I see is the president frantically reacting to the press of events." In an effort to explain itself, the administration summoned a small group of generally-sympathetic wonks to the West Wing. Brian Katulis, for one, walked away unconvinced, puckishly tweeting: "Can you help me find something? I'm looking for that Obama doctrine on national security."

The problem, of course, is that the president is committed to not applying a single, simple frame to a complex and evolving world. Doctrines are antithetical to pragmatism. Yet in our increasingly democratic age, as the electorate insistently wrests control of foreign affairs away from the mandarins, they are also indispensable tools of persuasion. And a president who cannot persuade the public of his approach, tying together disparate policies into a convincing package, risks losing the ability to implement or sustain his vision.

This is the paradox of pragmatism: the flexibility most likely to produce success is often least likely to consolidate political support....