The state of Soviet-US ties is so chilly at present that President Reagan's behind-the-scenes remark Aug. 11 about bombing the Soviet Union probably will not further endanger the two nations' relationship, experts say.
But it is likely to be used for propaganda purposes in the USSR and Soviet-bloc countries.
The White House and State Department are quietly ignoring the President's widely reported remark, but it has drawn negative reaction in European capitals. Nor has the issue received widespread front-page attention in this country.
While making a voice check before his radio broadcast last Saturday, President Reagan was recorded as saying: ''My fellow Americans, I am pleased to announce I just signed legislation which outlaws Russia forever. The bombing begins in five minutes.''
The remarks were considered by the White House ''off the record'' but they were recorded and word of them leaked out to the press.
''It was a careless and damaging remark, and it will be kept alive in Eastern Europe and countries hostile to us,'' says Jacob Beam, a former United States ambassador to Moscow.
''Reagan wouldn't think of adopting such a course. But it may conform to the mood of a lot of Americans so he does not lose completely,'' according to Mr. Beam.
''It will make an impression on the Soviet people,'' says Dimitri Simes of the Carnegie Endowment for International Peace.
''It is legitimate to ask why we should spend money on Radio Free Europe and Voice of America when one remark like that undoes everything we try to do in our public stance.
''This speaks louder than all the transmitters in the world,'' says Mr. Simes.
''It reflects on a man's judgment when even in unguarded moments he makes jokes about something as serious as that,'' comments David Newsom, director of Georgetown University's Institute for the Study of Diplomacy.
From his early days in office Mr. Reagan's dealings with Moscow often have reflected his strong anticommunism and dislike of the Soviet Union. At one point , for example, he characterized the USSR as ''an evil empire.''
In recent months, however, Reagan has sought to dispel the image of intractability created by such public postures.
''It would be serious enough if it had come in the wake of a demonstrated command of the defense and arms control field and a real effort to make progress ,'' says William Maynes, editor of Foreign Policy magazine and a former diplomat.
''But it comes in the wake of precisely the opposite,'' Mr. Maynes continues.
''The comment not only contributes to the belief that Reagan has not mastered this field but shows his irresponsibility about it.''
Mr. Reagan has demonstrated an extraordinary ability to ride out diplomatic gaffes.
President Jimmy Carter, for instance, was hounded in the press when he suggested, after the Soviet invasion of Afghanistan in 1979 that now he understood the nature of Soviet society.
Before him, President Ford took considerable public flak for suggesting Poland was not under Soviet domination.
Reuters reports from Moscow:
[In the first reaction Tuesday to Reagan's remark, made in microphone test before a radio broadcast, Soviet state television commentator Genrikh Borovik said on the main evening news:
[''It is said that the level of a joke corresponds to the level of a person's thinking. If that is so, then are not both too low for the president of a great country.''
[Borovik said Reagan's phrase had been ''astonishing.''
[The commentator said that in the first years of his presidency, Reagan had followed a tough line toward Moscow but had wanted to appear wiser and more mature in election year.
[Borovik said Reagan's aides had tried to explain the comment away, saying it was the President cracking a joke.
[''We understood, we understood very well,'' he said, adding that the press would not have picked up the comment had it not been an idea associated with the President.
[As the television news bulletin broadcast Borovik's commentary, the official Soviet news agency Tass published a report quoting foreign and US reaction to the President'swords.
[The West German newspaper Frankfurter Rundschau said: ''There are things a man in public office, in particular the president of the most powerful nation in the world, should not joke about, not even in private.
[''There can be no excuse for the latest example of the US president's humor. His words are dangerous and irresponsible.'']