President Boris Yeltsin of Russia has gained control of something more potent than Soviet artillery: the Soviet archives. His careful release of previously shrouded secrets can shed light on dark corners, end mysteries and replace suspicion with truth. Not to mention win friends abroad and damage enemies at home.
The release of documents on the Katyn massacre of 1940 and the shooting down of a South Korean airliner in 1983 are cases in point. The first nails down historical certainty that the dictator Josef V. Stalin and the Politburo ordered the execution of some 20,000 captured Poles in 1940. Incriminating documents including the Soviet dictator's signature on the order were turned over to Poland's President Lech Walesa.
The world first heard of this as Nazi German propaganda in 1943. The Germans said they uncovered the mass graves. They sought to sow dissension among World War II allies. England and the United States officially disbelieved the story, though Polish emigre communities were susceptible. After the war, historians came to believe the account. Soviet counter-accusations were unconvincing. The last Soviet president, Mikhail S. Gorbachev, apologized to Poland for the atrocity in 1990. Now the story is absolutely authenticated. The massacre was Soviet high policy, not the work of a deranged general. No unsettling mystery about this crime against humanity remains.
But in presenting documents on the downing of KAL 007 and the deaths of 269 South Koreans and Americans, Mr. Yeltsin may have cleared up little. Now it is known that the Soviets recovered the airliner's flight data recorder and cockpit voice recorder from the sea, and that the Politboro supported the decision after the fact. What has been translated so far, however, does not explain why the airliner had strayed 300 miles or who ordered it shot down for what reason.
What both sets of revelations do is tarnish the reputation of Mr. Gorbachev. It is clear that in 1990 he knew but did not reveal the extent of the complicity of Kremlin rulers in the Katyn massacre. It is also clear that he was part of the Politboro decision in 1983 to approve shooting down the airliner. Mr. Yeltsin has won the deserved thanks of Polish, South Korean and U.S. governments for these acts of candor. But he has also helped to damage his principal rival at home.
The number of officials in Russia and the West who are quaking at what else Mr. Yeltsin might reveal must be breathtaking. When a closed society opens up, there is no telling what will come out. Mr. Yeltsin finds himself the gatekeeper of 70 years of Soviet secrets. Control of information is power, and he can be expected to use it in the Russian interest and his own.