"Political scientists like to speak of "security dilemmas": situations in which one state acts to make itself safer, but in doing diminishes the safety of one or more other states, which in turn try to repair the damage through measures that diminish the security of the first state. The result is an ever-deepening whirlpool of distrust from which even the best-intentioned and most far-sighted leaders find it difficult to extricate themselves: their suspicions become self-reinforcing. Because the Anglo-American relationship with the Soviet Union had fallen into this pattern well before World War II ended, it is difficult to say precisely when the Cold War began. There were no surprise attacks, no declarations of war, no severing even of diplomatic ties. There was, however, a growing sense of insecurity at the highest levels in Washington, London, and Moscow, generated by the efforts the wartime allies were making to ensure their own postwar security. With their enemies defeated, there was less of an incentive for these former allies, as they were coming to think of themselves, to keep their anxieties under control. Each crisis that arose fed the next one, with the result that a divided Europe became a reality."