The year 1956 showed that the Warsaw Pact had a much greater role than NATO in assuring control over its members. But that did not necessarily mean it posed a threat to countries not under its hegemony. This ‘dovish’ argument was given support by the Soviet XXth Congress at which Lenin's theory of imperialism was formally dropped. The final victory of communism, though still assured, would not now be reached as the successful outcome of a world war, since that would result only in mutual destruction. But where did this leave the ‘great contest’ between rival systems? Would this doctrinal revision usher in a long duration of peaceful competition, a contest which, assured of the superiority of its own system, each side expected to win? Equally, under the guise of coexistence, the Soviet side might continue to rearm for a final conflict, thus requiring Western vigilance and counter-action.

Super-power competition began to develop a dynamic of its own, driven in part by technological advance. The launch of the earth-orbiting sputnik (4 October 1957) was not simply a scientific achievement, important as a propaganda coup on the eve of the fortieth anniversary of the Russian Revolution. Taken with the previously successful test of a Soviet Intercontinental Ballistic Missile (ICBM), it showed that the Soviet Union had rockets powerful enough to land atomic weapons on any part of the Earth's surface.