IN RECENT days both the Nobel laureate Andrei Sakharov and the Soviet government, which exiled him to the city of Gorky, have rapidly upped the ante. Through his wife, Mr. Sakharov has issued two written statements criticizing Soviet actions. The government has responded with threats of physical violence delivered by gun-toting "hooligans," threats of commitment to a psychiatric hospital and threats of possible sanctions against Mr. Sakharov's wife. Mr. Sakharov's response: "I refuse to submit them, in awareness of the consequences this can bring upon me and my wife." The momentum thus established could easily lead to psychiatric incarceration, to a trial on charges of treason, or worse.

The response in the West has been rapid also. In this country, a group of prominent scientists, including five Nobel Prize winners, quickly announced that they had signed a pledge asserting their refusal to participate in official scientific exchanges with the Soviet Union until Mr. Sakharov is released from internal exile. The pledge is now being circulated among scientists across the country. In West Europe, governments are feeling unaccustomed pressure from scientists and other intellectuals to protest the Soviet moves against Mr. Sakharov.

All this could come to a head two weeks from now, when delegations of scientists will meet in Hamburg, Germany, for what is called "The Scientific Forum." The delegations will be representing nations that are parties to the Helsinki Accord, and will be discussing scientific exchange agreements and other aspects of that much-abused accord. As has happened with previous Helsinki functions, the quasi-official U.S. delegation is struggling over the position it will take, but this time the questions are posed with a new starkness: Should it speak honestly? Will straight talk provoke a Soviet-bloc walkout? And which is worse, a ruptured meeting or a hypocritical one?

It seems likely that the breaking of ties between Soviet and American scientific communities is more than the Soviet government bargained for when it decide to try to silence Mr. Sakharov. Indeed, the affair has serious implications for both sides because scientific exchange and cooperation, and scientific expert opinion, have been a basis for efforts at arms control. The future of any strategic arms accords should be decided on the basis of their contribution to U.S. national security, but the political fact remains that ratification would be harder to achieve if Mr. Sakharov is in danger.

All this may seem like a great deal to hinge on the fate of one man -- even the man called by one of his colleagues, Lev Kopelev, "the conscience of Russia." Since he wrote those words, Mr. Kopelev has been accused by the Soviet press of being "a traitor to his country and his nation." Mr. Kopelev was in good company, however: Four years earlier, the Nobel committee had called Mr. Sakharov "the spokesman for the conscience of mankind."