Soviets Quietly Approve Prague Shake-Up : East Bloc: Eastern Europe has changed so much that Czechoslovakia’s reforms are seen as almost routine.

Twenty-one years ago, the Soviet Union sent its troops into Czechoslovakia to install an orthodox Communist leadership in place of the liberal reformers and their “Prague Spring.” The gains of socialism, Moscow declared, would always be defended everywhere.

When that Soviet-installed leadership was swept from office over the weekend, still clinging to communism’s old and rigid doctrines, the Soviet Union reacted with quiet approval.

Not only had the Prague leadership lost popular support, Moscow said, perhaps it had even been illegitimate from the beginning. And nothing was said about defending socialism.

Soviet television’s main nightly news program, “Vremya,” on Saturday showed the huge crowds in the streets of Prague cheering the ouster of the old Communist Party leadership. The Soviet correspondent explained in friendly, approving tones their hope that Czechoslovakia now is about to embark on a course of fundamental reform.

In its initial reports, the Soviet media treated the developments with sympathy--but as almost routine. A senior editor at the Tass news agency remarked that after similar events in Bulgaria, East Germany, Hungary and Poland, the changes in Czechoslovakia were, as he put it, “to be expected.”

So much has changed, first in the Soviet Union and more recently in much of Eastern Europe, that Moscow had actually grown impatient for Czechoslovakia and the other East European laggards to catch up--to adopt the new policies of political openness, economic reform and democratization that are now transforming the other East Bloc countries.

“Society as never before needs a reasonable dialogue,” the Soviet Communist Party newspaper Pravda said in a commentary from Prague before the leadership’s resignation. “It is very important that each side can express its point of view and listen to the other.”

But Czechoslovakia, of course, differs significantly from the other East European countries, for it had begun its own reforms in 1968--only to see them crushed by the tanks of the Soviet Union and its Warsaw Pact allies.

Much like the measures now promoted by Soviet President Mikhail S. Gorbachev, the Prague Spring reforms were meant to give socialism “a human face”--in the words of former Czechoslovak party leader Alexander Dubcek--by opening the political system to broader participation, by developing a mixed economy and by easing the country out of the East-West confrontation.

Appraising the August, 1968, intervention under the late Leonid I. Brezhnev, prominent Soviet writer Daniil Granin wrote in the current issue of the avant-garde newspaper Moscow News that much time was lost here, as well as elsewhere in Eastern Europe, in reforming socialism as a result of the crushing of the Prague Spring.

“The dream of perestroika belongs to you,” Granin wrote, addressing his friends in Czechoslovakia. “Your economic ideas, democratization and glasnost-- that was all begun by the Prague Spring.

“And if the Brezhnev clique had not smothered your perestroika , how much easier it would be for us now.”

The past 20 years “show us exactly what could happen if perestroika is defeated,” Granin continued. “A swathe of vengeance swept aside the flower of the nation and snuffed out the energy, the thought and the enthusiasm of not just the intelligentsia.

“How many lives have been wrecked and people destroyed, and how much disillusion, bitterness and spite have built up over these years for your own dogmatic Stalinists who triumphed then--and for us, their protectors?”

The Soviet Union had been gently pushing Czechoslovakia for several months toward fundamental reforms, just as it had East Germany and Bulgaria.

Gorbachev, commenting last week on the latest developments in Eastern Europe, told journalists that leaders in the region had misjudged events in the past and that rapid change is needed now “to make up for lost time.”

The Prague leadership was publicly nudged a week ago when Vadim A. Medvedev, the ideology chief of the Soviet Communist Party, told his Czechoslovak counterpart that the events of 1968 needed to be “reassessed,” and the Czechoslovak party newspaper Rude Pravo published this in an article from Moscow.

The intention was to “tell our comrades in Czechoslovakia that we would not stand in the way of reforms and that we in fact encouraged them to take an honest look at their current situation and at history,” a Soviet foreign affairs analyst said.

“What that really told everyone was that we would not intervene, that 1968 had been a mistake that they should now correct, and that we favored this very course of action.”

Moscow’s attitude has evolved over the past six months as developments have raced ahead of policy throughout Eastern Europe. Even last week, “Vremya” was describing the demonstrators in Prague as “anti-socialist” and the street politics there as threatening the country’s stability. On Saturday, Tass correspondents in Prague used as a counterpoint in their story on the leadership changes all the problems that faced opposition groups in agreeing on their goals and strategy.

The Soviet Union’s willingness to cooperate on a continuing basis with the new leaders now taking office in Eastern Europe was praised here Saturday by Poland’s non-Communist prime minister, Tadeusz Mazowiecki, who completed two days of talks with Gorbachev and Prime Minister Nikolai I. Ryzhkov.

“We have reached mutual understanding,” Mazowiecki said. “This is an important factor, the most important objective of this meeting. And this was an unusual, even extraordinary visit.”

Mazowiecki said that he had reaffirmed the intention of his government, a coalition in which the Solidarity labor movement and its allies are predominant, to improve and strengthen Poland’s ties with the Soviet Union even as it transforms its political and economic system.

Good relations with the Soviet Union help to promote stability in Europe and thus to preserve peace on the Continent, Mazowiecki said.

“These relations are of great importance to us . . . (and), under the new conditions prevailing today, we can create a wider public consensus or support for them,” he said.