IN THE midst of so much change within the Soviet Union, the impossible suddenly becomes real. In that light, yet another change is likely: an end to the "cold war" between the Moscow Patriarchate of the Russian Orthodox Church and the estranged Russian Orthodox Church Outside Russia.

At first glance, this seems no more than a historical footnote. The two churches have been split since the Bolsheviks came to power in 1917 -- at which point Patriarch Tikhon proclaimed communist activity "a satanic act." He excommunicated the Bolsheviks from the church before giving special permission for the establishment of the Russian Orthodox Church Outside Russia in 1920. First headquartered in Yugoslavia, the church moved to New York in the early 1950s, from where it has continued to oppose those who favored the Moscow Patriarchate.

The Moscow-based church has in excess of 50 million followers and the New York breakaway church only 50,000 members worldwide. But in spite of its relatively small size, there would be considerable significance in a reunification. It would mean, for example, that bishops of the New York-based church would be eligible to head the Russian Orthodox Church in Moscow, much the way a cardinal in socialist Poland became pope of the Roman Catholic Church. What's more, reunification would mean that bishops from the New York-based church could vote on various issues, and could become an independent force within the Russian church. It should also be noted that many in the New York-based church have monarchist leanings. In parishes around the world, one may still see portraits of Emperor Nicholas II and Empress Alexandra -- murdered by the Bolsheviks -- prominently on display. An annual memorial service marks the day that the royal family was executed.

Until recently, relations between the churches have been so strained that parishioners and clergymen of the New York-based church are still officially forbidden by their hierarachy to have any contact with the "Red Church"; Patriarch Pimen and other high-ranking Moscow clergymen were considered under the control of the Kremlin and therefore not to be trusted. The hostility was hardly one-sided. In the eyes of the Moscow Patriarchate, the New York-based church was a nest of schismatics.

But Patriarch Pimen died last month, after 19 years in office. And since Gorbachev came to power in 1985, the New York church has softened its policy towards the Moscow Patriarchate. The change has been noted by the church's clergymen and its parishioners, who report hearing such words as glasnost and perestroika during sermons and parish hall lectures. The death of Pimen led last week to the election, for the first time, of a non-Russian to the Moscow Patriarchate. Metropolitan Alexi, an Estonian, is known to be a strong supporter of Gorbachev's reforms, though not as someone who has challenged the Kremlin's authority.

The first public acknowledgement of the possibility of a reunification surfaced two years ago when Pimen asked the New York-based church to unite for the celebration of the millenium of Christianity in Russia. At that time, Metropolitan Vitaly, head of the Church Outside Russia, refused to come, but responded in a letter, "Let us await the results of the 'all-encompassing renewal,' believing that what is impossible today may become possible tomorrow."

Then, the shift of power within the New York-based church from hard-liners to change-oriented bishops created a favorable foundation for overcoming differences between the two churches. This was recently observed in an article in the liberal weekly Moscow News, which stated, "On the part of the Church Outside Russia, a certain warmth has been in the air since Metropolitan Vitaly became the head of its administration."

This "warmth" has been stretched even to an act of official gift-giving. According to an article in a Moscow Patriarchate publication, the Russian Orthodox Church Outside Russia presented a copy of the wonder-working Kursk Icon of the Mother of God to the archbishop of Kursk, who later called for the reunification of all the Russian Orthodox Christians inside and outside of the Soviet Union. The New York-based church is now even considering opening parishes in the U.S.S.R., in response to requests from Russian Orthodox clergymen.

Meanwhile, it is inevitable that the Moscow-based church will continue its rapprochement with New York. Both parties may publicly deny that negotiations are under way, but a number of present and former clergymen with ties to the New York church concede that reunification is only a matter of time -- with the caveat that the new patriarch is still untested. How extraordinary it would be if Mikhail Gorbachev's reforms also led to reunification of the estranged Russian churches -- and, from there, a restoration in Moscow of the church of the czars.

Anna Sypula, a Washington journalist and native of the Ukraine, immigrated to the United States in 1984.