Nearly 67 years ago, the American diplomat George F. Kennan laid out the strategic framework that would define the towering rivalry between the Soviet Union and the United States. We came to know it as the Cold War — as real and in some ways as dangerous as a hot war, an overshadowing, winner-take-all ideological conflict juxtaposing communism and democratic capitalism, played out through diplomacy and small-scale conflicts in lieu of the unimaginable alternative: total nuclear conflagration.