Ever since the atomic bombings of Japanese cities in August 1945, the world has been living on borrowed time, for major governments have been too committed to traditional thinking about international relations to resist the temptation to build nuclear weapons and threaten their use. Even so, thanks largely to popular pressure, governments have accepted some degree of nuclear constraint and nuclear war has thus far been averted. With a revival of public pressure and the implementation of measures to ensure international security, it still remains possible to safeguard human survival.