If Poland's experiment in developing a more democratic form a communism succeeds, much of the credit will have to go to the country's powerful Roman Catholic Church.

The church, together with the presence of a Pole on the papal throne, has played a vital role in shaping events in Poland over the last year. Last summer the church provided workers in Gdansk with essential moral support -- a prerequisite for the success of the strike.

Since then, the restraining hand of the primate of Poland, Cardinal Stefan Wyszynski, has been visible at crucial stages of the crisis. On several occasions, he has acted as an intermediary between the independent labor movement Solidarity and the Communist authorities, defusing one dispute or acting as respected arbiter in another.

The 79-year-old cardinal, who has led the Polish church since 1949, is known to have been deeply worried at the possibility of Soviet intervention in Poland. His overriding concern has been to preserve the country's national idenity.He has warned Solidarity's leaders of the dangers of going too far and at the same time he has insisted that the government carry out promised reforms.

Lech Walesa has displayed an open reverence for the cardinal, praising his wisdom and describing him as "my number one adviser." Solidarity has adopted the cross and other church symbols as its own. Many union members wear lapel badges depicting Pole John Paul II or the Black Madonna of Czestechowa, Poland's patron saint.

This esteem for the church stems from the fact that it is regarded by many Poles as the guardian of Polish sovereignty. Unlike some Catholic leaders in Eastern Europe, Wysznski never capitulated to official pressure. During the Stalinist years, his defiance led to his banishment to a monastery, but he returned in triumpth to Warsaw in 1956.

Ninety percent of the Polish people are Roman Catholic and the strength of the church has marked Poland off from the rest of the Soviet Bloc. It is the distinguishing feature of what has been called "the Polish road to socialism." Even the Kremlin recognizes that any government in Warsaw must come to terms with the power of the Catholic Church.

Many Poles believe that the upheavals of 1980 were set in motion partly by the election of Cardinal Karol Wojtyla as pope in 1978 and his visit to Poland the following year. During the visit, the state authorities withdrew into the background, leaving the church responsible for maintaining order among the huge crowds. The result was an impressive display of collective discipline that one participant described as "our first experience in self-government."

The papal visit brought confidence and hope to the Polish people. It was also a reminder of Poland's 1,000-year Catholic tradition, against which 35 years of Communist rule appeared insignificant.

Both the pope and Wyszynski take the long view of history. They are grateful for the concessions granted to the church over the last few months, including the broadcasting of religious services and the appointment of a Catholic as deputy prime minister. But they see these gains as of no value unless they are made permanent which means, above all, ensuring Poland's independence and sovereignty.

The Poles place great store in historical prophecies. One of the most dramatic, made by a Polish poet more than a century ago, was that one day a Slavic pope would ascend to the throne of St. Peter. Such would be the strength of his personality, wrote the poet, that he would guide whole generations toward light and justice.

Many Poles believe this prophecy has been fulfilled by Pope John Paul II. What is mentioned less frequently is the poet's further prediction that the election of the Slavic pope would herald terrible events, including war and civil strife.

Tantalizingly, it is not clear from the prophecy how this new dark era is supposed to begin.