For decades now the declaratory nuclear policy of the United States has stressed deterrence through the threat of massive punishment by attacking an aggressor’s homeland. Yet the doctrine has few friends willing to vocally support it and many politically diverse opponents. Most recently, President Ronald Reagan, who would have to give the orders for such a punishment, declared the doctrine immoral and called for its replacement in his so-called Star Wars speech of 1983. Now suddenly the concept of active missile defense is attracting supporters, again from throughout the political landscape—although with differing visions of what missile defense should become.