THE DEATH OF THE Soviet Union's most mysterious and short-lived ruler Yuri V. Andropov was announced last week, leaving his successes a myriad of domestic and foreign policy problems, not the least of which is the current chill in superpower relations. While it is hard to mourn a man for all intents and purposes dead for several months--who became a frightening parody of the fabled Big Brother of George Orwell's 1984. Andropov's death serves as a depressing reminder of how little progress the U.S. and the Soviet Union have made in this decade.

The prospects do not look good for any sort of improvement in the near future, especially since any of Andropov's possible successors are firmly indoctrinated with party politics, or what now passes for Marxist-Leninist ideology Konstantin U. Chernenko, the odds-on favorite, Mikhail S. Gorbachev, Grigory V. Romanov, or any of the other party bigwigs who may fill Andropov's spot will probably serve as the front-man for the ruling Politburo at least for several years. As with the past five Soviet rulers, power consolidation will undoubtedly come slowly.

That is why President Reagan should use Andropov's death as a chance to improve the abysmal lack of dialogue between the adversaries. The uncertain power structure in the Kremlin makes it unlikely that the Soviets will differ substantially from their previous negotiating positions in the suspended INF and START talks in Europe. President Reagan, with his usual obstinate confidence, has assured the American public that the no-longer "evil empire" will return to the negotiating table on its knees and with roses in its teeth. But the truth is that the U.S. must make the first move by softening its stance on Euromissile deployment, an area where we are most politically vulnerable.

Reagan already flubbed the opportunity to lessen the dangerous cold war mentality that has descended on the superpowers by sending his vice president. George Bush, to Moscow in his place. Reagan's snub, coming on the heels of a similar turn-down upon Leonid Brezhnev's death, only underscores his lack of understanding about the finer points of superpower relations.

"While our governments have very different views," Reagan said in his weekly radio broadcast Saturday. "our sons and daughters have never fought each other. We must make sure they never do." Reagan now has the opportunity, and therefore the responsibility, to make sure that his words become more than an ironic epitaph.