I N THE LATE 1980s Edward Teller, the father of the hydrogen bomb, and Lowell Wood, an astrophysicist, proposed a seemingly bizarre scheme to defend America against missile attack. The “Brilliant Pebbles” system envisaged thousands of small satellites in low-Earth orbit,

For decades, the idea of a nationwide missile defense system has captured the imagination of American leaders. During the Cold War, President Ronald Reagan introduced the Strategic Defense Initiative,