The horrific massacre in Paris reminds us of the Achilles' heel of American foreign policy. Ever since World War II, our foreign policy has rested on an oft-silent presumption that shared prosperity is a powerful and benevolent force for social stability, peace and (often) democracy.

All the emphasis on free trade and globalization is ultimately not a celebration of economic growth for its own sake. It's a means to larger ends of social cohesion and political pluralism.

In this, we have mostly projected our own domestic experience onto the world at large. Americans' obsession with material progress — which seems excessive and even vulgar to many — is largely what has enabled us to be a multiethnic, multicultural, multiracial and multireligious society.