Initiated by President Reagan in the mid-1980s, the Strategic Defense Initiative (SDI) popularly known as "Star Wars," would defend against nuclear missiles, using an array of technologies, such as anti-missile-missiles launched from aircraft, satellites designed to focus intense energy beams on missiles in the upper atmosphere, and ground-based laser-beam projectors. This last device, set against the backdrop of the Russian invasion of Afghanistan, is the focus of The Cardinal of the Kremlin.

As this novel opens, the Soviet Union and the U.S. are each close to perfecting a laser-beam device that could accurately shoot down missiles. One side has solved the problem of generating enough power to kill a missile; the other has solved the problem of targeting missiles accurately enough to score a direct hit with the beam. The side that learns the other's secrets first will have an effective defense against incoming...