The Soviet Union warned Poland's leaders today that they bear "special responsibility" for effectively checking the independent trade union Solidarity because it constitutes a threat to "the vital interests" of all socialist countries.

The warning in the Communist Party newspaper Pravda came two days before an expected meeting of the Polish party's policy-making Central Committee. It appeared designed to strengthen those in the Polish leadership who are prepared to risk confrontation with Solidarity by drawing a clear line and refusing further concessions.

Diplomatic analysts here said Moscow believes the Polish hard-liners are now in a stronger position with Poland's economy continuing to crumble as the grim winter begins to close in. There was speculation in East European circles here that there may be new personnel changes in Warsaw after the plenum.

The Pravda commentary was signed by Alexei Petrov, the pseudonym used to convey authoritative Kremlin views without resorting to a formal government statement.

After rejecting all aspects of Solidarity's program, which it called "the program of the antisocialist forces," the commentary repeated earlier Soviet assertions that Solidarity has become an instrument of political struggle and a "tool for undermining the state system." This, it added, "would not be tolerated anywhere."

In connection with the West, the commentary continued, Solidarity wants to break up the Soviet Bloc "by beginning in Poland." It added that all countries "which have chosen the path of socialism" were endangered.

"The preservation of the revolutionary gains of the Polish people is not only their domestic question. It is a question directly affecting the vital interests of all the peoples and states which have chosen the road to socialism. All this places special responsibility on the Polish working people and on the party and government leadership of the country," it said.

The commentary, despite its total rejection of Solidarity, was measured in tone and seemed to be addressing a Polish audience.

Western analysts said its timing suggested that Moscow would like the Polish plenum not only to endorse a tougher line but also to abandon hesitation that has produced a power vacuum in Warsaw with nobody having the authority to act without the agreement of the union and the Roman Catholic Church.

In this context, the commentary indirectly criticized Polish communist leader Stanislaw Kania by referring scornfully to "the so-called renewal" policy under which "the socialist foundations of the Polish society are being undermined."

It said that "antisocialist forces" are using Solidarity to seize state power and that they are being supported by "international reaction" and by "reactionary Catholic clerics."

Most of the Soviet objections to the Solidarity congress and its program have already been raised in the Soviet press. The commentary, however, has drawn them all into a cogent Soviet position. It was interpreted by Western diplomats as part of the continuing Soviet effort to use political means to influence the course of events in Poland.