Moscow — The new Polish leadership's muscle-flexing toward union extremists and reported moves to bring Solidarity into a ruling coalition have met with thundering silence from the Soviet Union.
The assumption among diplomats here is that the Kremlin is taking a wait-and-see attitude toward Polish Communist Party chief Wojciech Jaruzelski, who replaced Stanislaw Kania Oct. 18. Some analysts go further, speaking of a ''honeymoon'' of sorts between the Soviet Union and the new party leader.
''I think the Soviets want to avoid complicating Jaruzelski's task,'' remarked one Western diplomat Oct. 26 amid reports that Polish troop contingents were being sent to rural areas to facilitate law, order, and the distribution of food supplies.
The Soviets, while publicly leaving policy options open, have for some time seemed reluctant to broadcast at home the most potentially alarming Polish developments. Charges in an official Soviet letter to Warsaw last month that ''anti-Sovietism'' had reached ''dangerous limits'' and that Soviet troops there had been ''subjected to threats'' have still gone unreported in Moscow.
This news media strategy could be a further explanation of the Soviet press silence, at this writing, on the latest Polish military move and on various wildcat protests in Poland since General Jaruzelski, already premier and defense minister, became party chief.
''Honeymoons,'' particularly political ones, have a way of ending. Even in a warmly worded congratulatory message to the new Polish leader Oct. 19, Soviet President Brezhnev made it clear he looked to General Jaruzelski to shore up the ruling party and turn back ''counterrevolution'' in Poland.
Ultimately, the Kremlin attitude toward the Polish communist chief seems likely to depend on the extent to which he proves equal to these tasks.
But at this writing, the official Soviet media had said precious little, positive or negative, about the week-old tenure of General Jaruzelski.
Gone, for the time being at least, are past Soviet press suggestions that the Warsaw leadership was buckling under to the ''antisocialism'' and ''anti-Sovietism'' of Solidarity union extremists.
There have been no press reports here of Polish police moves against union activists allegedly spreading ''antisocialist'' propaganda.
Diplomats here presume the Kremlin welcomes the apparently tougher approach toward Solidarity.
It is less clear whether the Soviets support such a policy even at risk of violence in Poland. Widespread unrest could present the Kremlin with an urgent choice of whether to intervene.
The Soviets may have mixed feelings about reports Jaruzelski is weighing the idea of a widened coalition, bringing in Solidarity and representatives of the Roman Catholic Church.
To the extent that such a move could further dilute Polish Communist power, the Kremlin would probably feel uneasy. But to the extent that Jaruzelski's power base would be widened, the Communists' position protected, and Solidarity tied to the coalition's policy, the Soviets might feel differently.