UN General Assembly
1960

122. Neither can we depend too much on the thermonuclear weapon as a deterrent. There was a time, between 1945 and 1949, when the United States was the only country which had an atomic weapon. It was then truly a deterrent. Now, both the United States and the Soviet Union are known to possess large quantities of the most destructive atomic weapons, with a perfected system of delivery. But, as the arms race continues, it is not impossible for one of these countries to gain a definite superiority over the other, which might induce it to launch an attack. I do not suggest that it would happen, but it could possibly happen when a point had been reached of superior power. Retaliatory power no doubt is still a deterrent, but it may be thought that a first surprise blow may destroy the retaliatory power.