AS he sat through one long emergency session of the 15-man Politburo after another, Leonid Brezhnev may well have felt a twinge of envy at Richard Nixon's evident power to make quick foreign policy decisions on his own. Despite his pre-eminence as Secretary General of the Soviet Communist Party, Brezhnev is a member of a collective leadership whose decisions are reached only by consensus. Last week those deliberations were especially arduous, as Russia's ruling council coped with its most complex challenge in a decade: how to respond to the U.S.'s mining of North Vietnamese harbors.
Nixon's move forced the U.S.S.R. to...