Moscow prefers either to crush with tanks and guns a dissenting and misbehaving East European satellite government, or maintain the external appearance of total harmony with it.
This past week, when East Germany's Erich Honecker postponed with open regret his planned visit to West Germany, we saw the culmination of one of the most flagrant examples since World War II of an open and public disagreement over a vital matter of policy between Moscow and one of its most important allies.
There have been plenty of disagreements before between Moscow and the capitals of its clients in Eastern Europe. But on those previous occasions the West usually learned about the disagreements by reading between the lines or by clandestine ''leaks'' of information.
This time the row is out in the open and can be documented from the public record. Moscow dislikes, strongly, the detente which Mr. Honecker in East Berlin has been pursuing with the government of West Germany in Bonn. Moscow has made its displeasure known both in the press at home and in publications in Eastern Europe.
East Germany has been benefiting from that detente, and so too has Moscow benefited indirectly. The detente has involved extensions of credit to the East German economy and the transfer, often unofficially and sometimes clandestinely, of Western technology. The high productivity of East German industry (the highest in any communist country) has been a boon to the people of East Germany. Some of that has spilled over into the Soviet Union.
But to have East Germany benefiting from a growing friendly association with West Germany runs counter to Moscow's current mood of growling isolationism from the West.
Honecker was scheduled to go to West Germany for a full formal, ceremonial visit during the last week of this month. He would have dined in state with West Germany's aristocratic president, Richard von Weizsacker. He would have had his first chance to see with his own eyes the economic wonders West Germany has achieved during the years of enforced division of Germany.
The substance of the detente will presumably continue. East Germany is already involved with West Germany in a web of economic and human associations which would merely have been symbolized by the formal visit. But clearly, the formalization was more than the Kremlin could take, particularly when it involves East Germany.
Ironically, the heads of government of both Romania and Bulgaria are also scheduled to visit Bonn soon. And Leonid Kostandov, a member of the Soviet Central Committee, would have gone, too, had he not died suddenly in East Germany.
But that is different. A Russian high official can go on a scouting mission. Bulgaria is the most loyal of the satellites. Romania is the most independent. Besides, Romania does not have Soviet troops within its borders and thus has an extra degree of independence.
East Germany is another matter. It is in Soviet eyes the supreme prize won by Soviet arms in World War II. It is regarded in Moscow as vital to Soviet military security. It is a military bulwark against the West, and also the main launching pad for any Soviet military advance westward.
The episode of the postponed Honecker visit to the West underlines an observation in the current issue of The Economist. The British news magazine noted that when this year opened, the main question in East-West relations seemed to be whether Western Europe would remain a reliable ally of the United States.
''In September, only eight months later,'' says The Economist, ''the main question seems to be whether Eastern Europe will remain a loyal ally of the Soviet Union.''
The plain fact is that the East German leaders, in spite of being devoted Marxists and ideological servitors of the Soviet Union and the Soviet system, have been reaching westward for closer associations of all kinds with West Germany.
And so, of course, have the other satellites in Eastern Europe. Even Bulgaria , a true and loyal ally of Moscow, seeks more access to the industries and technologies of the West. Its leader, Todor Zhivkov, would not be going to Bonn unless he too both needed and wanted more trade with the West.
A corollary to the above is that the new isolationism which Moscow has been practicing over the past eight months has weakened the Soviet system of alliances while at the same time strengthening the Western association. NATO is palpably more lively and cohesive today than it was eight months ago. The ordeal of the deployment of the new American weapons has been surmounted. Anti-American demonstrations have dwindled and all but disappeared from the NATO scene.
Soviet leader Konstantin Chernenko seems still to be nominally in charge in Moscow. He was brought on stage this week to honor three Soviet cosmonauts. But the postponing of the Honecker visit seems to be typical of a lot of other postponing of decisions in Moscow since the leadership was put in Mr. Chernenko's hands.
This has not been a strong or positive regime with a clear sense of direction. Most Soviet experts agree that we see in Kremlin behavior this year the symptoms of an interregnum. Chernenko's elevating seems to have been primarily a way of postponing the dreaded moment when the aged leadership will be forced to defer to the new generation.
About the most decisive thing they have done for months has been to tell Mr. Honecker to postpone his visit to West Germany. But even that is an evasive act. It avoids a yes or no decision on whether East Germany may continue to expand its detente with West Germany. Moscow is marking time.