Nevertheless, during the sixty years of the twentieth century many problems have come increasingly into the realm of acceptable public discussion.

It is immoral from almost any point of view to refuse to defend yourself and others from very grave and terrible threats, even as there are limits to the means that can be used in such defense.

Nuclear weapons are intrinsically neither moral nor immoral, though they are more prone to immoral use than most weapons.

My guess is that nuclear weapons will be used sometime in the next hundred years, but that their use is much more likely to be small and limited than widespread and unconstrained.

For some years I have spent my time on exactly these questions - both in thinking about ways to prevent war, and in thinking about how to fight, survive, and terminate a war, should it occur.

New developments in weapon systems during the 1950s and early 1960s created a situation that was most dangerous, and even conducive to accidental war.

The widespread diffusion of nuclear weapons would make many nations able, and in some cases also create the pressure, to aggravate an on-going crisis, or even touch off a war between two other powers for purposes of their own.