JIMMY CARTER is to meet Leonid Brezhnev in Vienna in a month's time for their first summit, and the meeting comes none too soon. As no other event can, the summit will force the leaderships of the two countries - and on the American side, the public as well - to look beyond the particulars of Soviet American affairs and to ask what the broad sweep of the relationship is and ought to be. This is not to ignore that the event will be of consuming personal and political importance for both summiteers, each in his fashion. But what it is necessary to focus on this time around is the element that has been most overlooked in the separate American debates swirling around SALT, human rights and the other particulars: how the pieces fit together.

Mr. Carter, to be sure, has not been inattentive to this matter. Early on he offered the Soviets a summit and, with it, the chance to work out a comprehensive relationship. But the offer came encumbered with American initiatives on arms control and human rights that unsettled the Kremlin, and meanwhile the Soviets were making unsettling moves of their own in the Third World and in arms building, and so nothing happened. That reduced Mr. Carter simply to stating what he wanted his Soviet policy to be: competitive where necessary, cooperative where possible. It was, as a formula, perfectly satisfactory, but a formula stated by one side is no substitute for a relationship worked out by both. This is what has been missing in Soviet-American relations perhaps at least since Watergate laid President Nixon low.

To understand where we are now with the Russians, it is necessary to go back to what might be considered the four-part vision that emanated from Henry Kissinger at the time of the first Nixon-Brezhnev summit in 1972. It made sense then and it makes sense now.

1. Geopolitically, the key was a close American tie with the People's Republic of China. Here, by normalization, Mr. Carter has stayed on course.

2. Strategically, the key was to maintain a certain prospect of balance or equivalence by discreet applications of arms control and arms building. On this score, you have to say the jury - the Senate considering SALT II - is still out.

3. Diplomatically, the key was to seek agreement - not just on paper but in practice - on a code of conduct or rules on engagement to prevent the inevitable contests for influence in Third World areas from getting out of hand. The Nixon-Ford-Kissinger team did not do well here, and the Carter team has not done well either.

4. Politically, the key was to weave a web of Soviet-American interests through trade, exchanges cooperative projects, etc., so as to give both sides a strong stake in responsible conduct in crisis times.This web did not get well woven in the earlier period, and in Jimmy Carter's term it has come almost completely undone.

Merely to offer this analysis is to suggest the thinness and poverty of current Soviet-American relations and their inadequacy when measured against the expectations, or goals, set at the beginning of the decade. One does not want to overdramatize the situation, but it is unhealthy and even potentially dangerous to have relations in this condition. To make this analysis is also to indicate the rough agenda for the Carter-Brezhnev summit: strategic questions, diplomacy in Third World areas, rebuilding or building a web of inter-locking interests.

Conspicuously missing from this list is the special emphasis Jimmy Carter has placed on what he chooses to call human rights and what the Kremlin not unreasonably regards - when the matter is pushed too hard too publicly - as unacceptable intrusion into its internal affairs. With Soviet cooperation, Mr. Carter can, at the summit, make some valuable if modest progress toward a more stable relationship with the country that it is most important for the United States to deal with sensibly. Or he can conduct a crusade.