Except for the presence of a visitor, it was just another dry run for doomsday. A captain and a first lieutenant of the Soviet Strategic Rocket Forces simultaneously turned two keys that would, in wartime, send hurtling toward the U.S. an SS-19 ballistic missile with six independently targeted thermonuclear warheads. Watching from a corner of the cramped underground control center was a tall, droll Yankee naval officer who describes himself as a "country boy from Oklahoma": Admiral William J. Crowe, 64, Chairman of the U.S. Joint Chiefs of Staff and the highest-ranking American military official ever to visit the U.S.S.R.
He...