For reasons of history and politics that are familiar to most, strategic defense until recently was relegated to the backwaters of the strategic debate on both sides of the Atlantic. Although the 1972 Antiballistic Missile (ABM) Treaty put an early halt to defensive competition, small, dedicated groups of research scientists and engineers in the United States devoted considerable energy to exploring the technical limits of ballistic missile defense (BMD) within treaty constraints. Several hundred million dollars have been spent each year since 1972 to finance these efforts. 1 Indeed, as the United States tried to address the growing problem of land-based intercontinental ballistic missile (ICBM) vulnerability, many proposed schemes included plans for modest ballistic missile defense deployments to enhance ICBM survivability. But the U.S. program attracted little if any high-level political attention. Within U.S. academic circles it received equally short shrift.