President Kennedy's elaborately casual way of preparing the American public for the Vienna summit conference is an indication that he wants the whole affair invested with as few expectations as possible. In this restrained approach to all such personal conferences he is acting wisely.

The purpose of most of the state visits to Washington this spring was to re-open lines of diplomatic communication that had sagged into disuse during the Eisenhower era. Not one of these visits produced any substantive policy change. They--like the impending talks with De Gaulle in Paris and the Vienna conference--are in fact not supposed to arrive at any substantive result.

Kennedy's line on all personal conferences is clear now, and must be kept clear when the May and June meetings with De Gaulle and Khrushchev are taking place: a summit meeting is not to make decisions or even to reassure American, French, or Russian opinion. It is to take soundings, to make positions clear, and to avoid the sort of misunderstandings that result in fatal policies. The three nations must expect nothing further from these talks than the knowledge that their leaders have had an opportunity to appraise each other.

It would be a great pity if the Administration built up hopes--almost certain to be dashed--that Kennedy's talks with De Gaulle will end in some kind of new entente. France is not likely to change her desire to wield an independent bomb, and De Gaulle is not likely to be any the less adamant on the need for a revised NATO command structure.

What can be accomplished by Kennedy in conferring with De Gaulle will not be seen by the public: he can case the old man's suspicion that France is the dummy partner of the Western alliance, and he can make some personal amends for the CIA's alleged meddling in Algeria and in the French legislation on nuclear weapons--no doubt by recounting some of his own grievances against that body.

Even less of weight will come out of the Vienna summit conference. Almost anyone can predict what the agenda of the meetings will be. And nearly no one at this point expects any real Russian or American changes of heart on Berlin, Laos, Cuba, or even disarmament.

If, as Kennedy feels, things are much more tense now than at the time of Camp David, then it is all the more important that this zero level of public expectation continue. If Kennedy can avoid the kind of inflated optimism and subsequent letdowns that followed Geneva, Camp David, and Paris, then the summits can once again become useful in their own limited way.