"Since the advent of the nuclear age, humanity has existed and 'progressed' in a politico-military climate increasingly threatened by the possibility of instant annihilation. The prevailing condition now is one in which two superpowers possess and control the means, many times over, to terminate life as we know it on this planet. The nuclear capacities of the United States and the Soviet Union alone equate to roughly two and one half tons of dynamite for each person on the earth.' In this bipolar world, in which the antithetical political ideologies of the two superpowers continually and almost daily conflict with each other at varying levels of intensity, a state of mutual nuclear fear has also existed. Although it cannot be empirically proven, it appears that this state of mutual fear (i.e. the fear that one nation would inflict a nuclear counterstrike of unacceptably devastating proportion against the other, should the other strike first) has successfully ensured that to date these weapons of mass destruction have not been used to settle political differences. This threat of retaliation, in several variations, has become the bedrock of a general philosophy (I hesitate to say strategy) referred to as 'deterrence.'"
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/
Parameters, Journal of the US Army War College. v.16 no.2, pp.16-25