There is an Ivan-One-Note quality to Soviet propaganda against the U.S. these days. Whatever the issue at hand -- trade, ideology, Third World instability -- Soviet spokesmen routinely find some way of working in a denunciation of Ronald Reagan's Strategic Defense Initiative. Part of the Soviet complaint is that SDI, commonly called Star Wars, has the potential of drastically changing the rules whereby the superpowers deter each other from starting a nuclear war.
For decades deterrence has rested on the threat of retaliation. Thus, for both sides, the ultimate defense has been the ultimate offense. Large-scale defenses on one side would...