For decades, Ronald Reagan’s Strategic Defense Initiative (SDI)—an ambitious ground- and space-based “shield” to protect the United States from nuclear ballistic missiles—has been mocked and criticized. First proposed by the president in 1983, it was immediately dubbed “Star Wars” by the mainstream media and dismissed as unscientific, infeasible and even counter-productive. The Union of Concerned Scientists, 100,000 members strong, was fierce in its opposition. The Arms Control Association declared that SDI would end arms control, while some Soviets felt SDI would end the world. Domestic critics became furious, and the Kremlin went ballistic.