Moscow opened a game in either diplomacy or propaganda when on July 29 it formally proposed a US-USSR conference in Vienna, beginning in September, to consider the possibility of preventing the ''militarization of outer space.''
We still cannot be entirely sure what was originally intended when this opening move was made. It could have been a detour around the breakdown in strategic weapons talks, a way of getting back into negotiations with the United States without violating Moscow's own contention that it will not go back to such talks unless or until the US takes back its Pershing II and cruise missiles now being deployed in Europe.
Alternately, it could have been a propaganda maneuver based on the assumption that Washington would turn it down and thus give Moscow the chance to pose before European and US opinion as the one most ready to negotiate and the US the one determined on the arms race.
The move hit a Washington where the staff at the White House is divided between those who oppose all serious arms negotiations and those who think the time has come to talk. The talkers won out when the Soviet note came on June 29 to the extent that it was decided to accept the Soviet proposal for the Vienna meeting in September, albeit with trimmings.
The response proposed that the talks in Vienna include strategic weapons as well as the matter of militarization of outer space.
Moscow promptly retaliated claiming that this was an unacceptable condition.
The White House countered by saying a delegation would be in Vienna in September ready to talk about outer space and anything else that might come up. The White House stated that it was accepting unconditionally.
Meanwhile, an anonymous high official in Moscow gave an interview to correspondent William Beecher of the Boston Globe, stating that in some Moscow quarters there was serious study about a whole new approach to the arms control problem lumping together all types of nuclear weapons.
In our edition of July 6 we cited the approach to Mr. Beecher as one reason why something useful might come out of the Vienna meeting. It certainly could if Moscow is ready for a new beginning on arms control in which all types of nuclear weapons could be considered under some new formula balancing off missiles with antimissiles and anything which could do harm in outer space.
But on July 9 we received a cable from Moscow signed by Alexander Malyshkin, a writer for the Novosti Press Agency, asserting that ''before the delegations of both sides come to the negotiating table they must reach agreement on the subject of the proposed talks. In early July Moscow specified once again that it invited the US government to the talks on preventing the militarization of space , and not to any other talks.'' (See below.)
The Novosti Press Agency speaks for the official Soviet position of the moment. We assume that Mr. Malyshkin's cable was speaking for the Soviet Foreign Office. On that assumption, it means that Mr. Beecher was either intentionally or unintentionally misled as to the possibilities of a new beginning on arms talks.
It also means that it is not Washington, but rather Moscow, which is attaching conditions to the meeting in Vienna.
Congress and the Western allies have been urging President Reagan to resume talks with the Russians, unconditionally. Moscow has been accusing Washington of attaching unacceptable conditions. That is precisely the present position of Andrei Gromyko, the Soviet foreign minister.
President Reagan has agreed to go to Vienna and talk, unconditionally. True, he wants to broaden the talks once the American delegation gets there. But he has not insisted on Soviet agreement to talk about other things as a precondition.
Moscow has put itself in a propaganda box. It has invited the US to talks on outer space, ''and not to any other talks.'' So plainly, Moscow is insisting on ''conditions'' surrounding the talks. Moscow has played this hand poorly. Mr. Reagan wins one.