On a visit to the United States 15 years ago, long before he became a contender for the job of patriarch of the Russian Orthodox Church, the Rev. Kirill Gundiaev was asked what Americans could do to help the faithful in his officially atheistic country.

"We always answered, 'Keep us in your prayers,' " Kirill, as he is called in his church, recalled. "Now we have many other answers."

Now archbishop of Smolensk and head of the church's Department of External Affairs, Kirill rattled off through an interpreter several things that Orthodox Church members, Moslems, Baptists and others need: religious literature, teachers and money to rebuild and refurbish the more than 2,000 churches that have been reopened in the past two years.

But what he cares about most is an overhaul of Soviet laws governing religious activity. Although technically here as head of a religious delegation praying for a successful summit, he skillfully weaves into each conversation the issue of Soviet law.

Joseph Stalin's decree forbidding religious "cults" in 1929 became the basis for shutting churches, imprisoning clergy and shutting down most official religious life.

The degree of activity individual congregations later got away with often depended on who was running the country.

Efforts to rewrite the law are underway, and Kirill, though not completely satisfied with the draft he has seen, says he believes there has been progress.

"I'm prepared to fight for that future in which the destiny of the church never depends on a kind or evil ruler," he said.

The Russian Orthodox Church is a part of the Eastern branch of Christianity, which separated from Rome in 1054. It claims 30 million to 50 million members in the Soviet Union, and about 750,000 adherents in an independent U.S. church.

Kirill, 43, is bishop of Smolensk, a city of 276,000 about 200 miles west of Moscow. He is a Breshnev-era renegade who under glasnost has become part of the church establishment. His name is mentioned as a potential successor to Patriarch Pimin, who recently died, when elections are held next week.

During interviews, Kirill doesn't hesitate to correct his interpreter; it seems he knows more English than he lets on.

Anyone in the Russian Orthodox hierarchy is viewed with suspicion by believers, according to authorities on Soviet life. Novelist Alexander Solzhenitsyn once denounced Orthodox bishops as feeble cowards who kowtowed to the Soviet government at the risk of cutting themselves off from their believers.

Kirill is savvy enough to acknowledge that church leaders have made mistakes, but he would like to leave the impression that the leadership is changing. "We are not a part of Gorbachev's team," he said in his opening statement Wednesday at a news conference at the Washington Cathedral. "We have come here independently to provide spiritual support for the summit."

If religious activity continues to accelerate in the Soviet Union, Kirill and his Orthodox colleagues will face severe problems. One of the most pressing is the question of ownership of 3,000 former Catholic churches in the western Ukraine. The church buildings were turned over to the Orthodox Church during the Stalin era, and Catholics want their buildings back.

Another hurdle is the increasingly vocal opposition of the Russian Orthodox Church Outside Russia, a dissident group with representatives in Europe and the United States as well as in the Soviet Union.

On both of these issues, Kirill talks tough. The Orthodox Chruch should continue to own many of the churches in the Ukraine, he said, because there are now more Orthodox Church members than Catholics there (Ukrainian Catholics dispute this). And the dissidents, he says, are not a threat.

Of course, he can't be sure. As his host here, the Rev. Dimitry Grigorieff said: "Everything is in some kind of commotion over there. We don't know yet what the result of all the those commotions are going to do."

Kirill will speak at Grigorieff's church, St. Nicholas Cathedral, 3500 Massachusetts Ave. NW, at 10 a.m. tomorrow.