Nearly 60 years ago, in July 1947, American diplomat George Kennan published what was to become the single most influential article in modern American diplomatic history.

Writing in the prestigious journal Foreign Affairs, and signing his piece anonymously with an "X," Kennan, who had been posted to the USSR before, during and after World War II, stated that "the main element of any United States policy toward the Soviet Union must be a long-term, patient but firm and vigilant containment of Russian expansive tendencies."

The word picked up from this by American policymakers was "containment."