... And in Moscow [ cf. A Shift in Budapest ... ]

JAWS are dropping again over yet another change in Moscow. This time it's Foreign Minister Eduard Shevardnadze's candid admission of Soviet error in invading Afghanistan and building a radar installation that violated the 1972 Anti-Ballistic Missile Treaty. Mr. Shevardnadze's contrite words concerning the radar, located at Krasnoyarsk in Siberia, were welcomed by American officials. For years, they've contended that the facility undermined the ABM treaty. Under President Reagan, Krasnoyarsk bolstered arguments that Kremlin ABM violations compelled the US to move ahead with its own missile-defense plans, including the Strategic Defense Initiative.

That rationale has now vanished, as Shevardnadze no doubt intended. This clearing of the air should inspire new and more fruitful discussions between Moscow and Washington on strategic missile reductions.

The admission of error in Afghanistan, while heartening to listeners outside the Soviet Union, was a forthright apology to the Soviet people for a costly mistake. The invasion decision, made by a small clique around Leonid Brezhnev, took place ``behind the backs of the party and the people,'' Shevardnadze declared to the newly popularized Supreme Soviet. Since both the radar and the Afghanistan venture were conceived under Mr. Brezhnev, the foreign minister was trying, perhaps more pointedly than ever, to distinguish the past from the Gorbachev present. A sense of change and momentum is politically valuable for Mr. Gorbachev, who is still struggling for an economic breakthrough.

Shevardnadze also made a clear statement of tolerance for the historic changes in Eastern Europe. He professed to understand the yearnings of Hungarians and Poles for more effective government and wider contact with the world.

The Soviets still put limits on what they can tolerate from activists within their borders or their alliance. But the limits are proving remarkably pliable.