The recent trial of two Russian writers, though it ended Monday in their conviction, may have been an important break-through in the struggle for civil liberties in the Soviet Union, Harold J. Berman, professor of Law, said yesterday. Berman, one of the country's leading experts on Soviet law, said that authors Andrel D. Sinyavsky and Yull M. Daniel are the first Soviet political defendents who were not pressured to plead guilty and who were permitted to have an active defense.

"They had a genuine trial," Berman stated. "They were charged with weakening the Soviet state. But they were allowed to challenge this description of their work. They had counsel and were allowed to present their writings as evidence."

Berman acknowledged that their convictions were a blow to Soviet writers seeking greater freedom of expression. "These men were heroes," he said. "They pushed the Soviet system to its limit."

"But it's no good to say that this is Stalinism, just Stalinism, all over again," he added. "Fifteen years ago, they would have been brought before a board of the secret police and been sent to Siberia or shot. The trial they had was public and what was said there is common knowledge by now among the intelligentsia."

Writings of Sinyavsky whose pseudonym is Abram Tertz, and Daniel, whose pseudonym is Nikolai Arzhak, have been smuggled into Europe in recent years. "Both are very hostile to what's sacred in the Soviet system," Berman said. Sinyavsky, for example, once likened Lenin to "a dog baying at the moon."

Sinyavsky was sentenced to seven years of forced labor and Daniel to five. Because they were tried in the Supreme Court of the Russian Republic, they have no rights of appeal.