Daniel Ellsberg:

Ellsberg was appalled to discover several things (that were not disclosed to the public): the military's plan was for a first-strike nuclear attack not for a retaliatory attack in the case of a Soviet first strike; the system was prone to false alarms, each of which could have started a nuclear war; China was a target too; every major city in the Soviet Union and China was going to be targeted; the original estimates, as horrific as they were, of casualties due to nuclear war did not contemplate the "nuclear winter" following a nuclear war; and, last but not least, the president was not the only person authorized to order a nuclear strike. The latter is easily explained: the plan had to account for the case that the president couldn't be reached while the Soviet were launching nuclear missiles on the USA. Therefore Eisenhower delegated others to authorize the launch of nuclear missiles.

The most shocking chapter is the one with the numbers. The USA had 3,000 nuclear warheads. In case of a nuclear war, the USA predicted (in 1961) that 275 million people would be killed in the first few hours in the Soviet Union and in China and 325 million would die within six months, plus one hundred million in Eastern Europe, up to one hundred million in Western Europe, and several millions in neighboring countries like Pakistan and Japan. Soviet retaliation on Western Europe would have killed another hundred million. Lynn Eden's book "Whole World on Fire" (2004) later calculated that firestorms would have killed hundred millions more, for a total of about a billion, i.e. one third of the planet's population in 1961. Then came the realization that nuclear war would cause a "nuclear winter": a decade of no sun and no rain that would starve to death most surviving animals, including most humans. Meanwhile, general Thomas Power assured president John Kennedy that a preemptive strike against the Soviet Union would kill "only" ten million people in the USA. Ellsberg tells the story of how close the USA and the Soviet Union came to nuclear war in October 1962 during the Cuban missile crisis. That was in 1961 when the USA had 3,000 nuclear warheads. By 1986 the USA had 23,317 nuclear warheads and the Soviet Union 40,159.