Brief History: Missile Defense

U.S. Navy / AP

An SM-3 interceptor missile is launched on July 20, 2009—the Navy's 19th success in 23 at sea firings.

President Barack Obama's announcement on Sept. 17 that he was scrapping plans for a long-range-missile shield in Europe prompted a fervor normally reserved for theological discussion. Critics assailed his alternative--smaller, sea-based interceptors to counter the immediate threat from Iran--as a concession to Russia, which had seen the U.S. stronghold near its borders as directed at its own arsenal.

A viable missile-defense system has long been the holy grail of U.S. military planners. One of the earliest national strategies, conceived during the Johnson Administration and based on research begun under Dwight Eisenhower, called for nuclear-tipped rockets that could head off an incoming...