In the poem “Mending Wall,” Robert Frost asserted that “good fences make good neighbors.”  World history is replete with foreign policy built around physical walls, from Emperor Hadrian, to the Great Wall of China, to the Berlin Wall, the wall between Palestine and Israeli, to the U.S.-Mexico border.  Containment and isolation have often been the cornerstones of policy.

Today we face a different situation, where “front lines” of conflict have blurred and disappeared, and non-state actors dominate the threat-scape. Instability in Iraq, Afghanistan, Syria, Kenya, Somalia, and elsewhere requires a different form of engagement. Important steps have been made in peace-building and post-conflict resolution, but so far we have not taken advantage of a major opportunity to use some of our