Imagine     Imagine there are still 27,000 nuclear weapons in the world, over 15 years after the end of the Cold War.     Imagine that 12,000 of these weapons are deployed, and that 3,500 of them are on hair-trigger alert, ready to be fired in a matter of moments.     Imagine that the use of a single nuclear weapon could destroy a city, and the use of a small number could destroy civilization.     Imagine the horror and devastation of Hiroshima, and multiply it by every city and country on earth.     Imagine that a nuclear war could end human life on our planet, and that the capacity to initiate a nuclear war rests in the hands of only a small number of men.     Imagine that nuclear weapons threaten the future of humanity and all life.