Zbigniew Brzezinski, the president's national security adviser, has chosen to redefine the nature of detente, and in so doing has broadened its scope far beyond anything envisaged by Richard Nixon and Leonid Brezhnev when they promulgated the agreement in May 1972.

Brzezinski now charges that Russia has broken the "code of detente." His bill of particulars charges that the Soviet Union has been engaged in a "sustained effort" to build up its military power, to strengthen "its forces on the frontiers of China," to maintain a propaganda campaign against the United States, to "penetrate" the Mideast, to stir up difficulties in Africa and "perhaps to seek more direct access to the Indian Ocean."

All, or most, of those actions may be offensive to Brzezinski and to Americans in general, but do they constitute definite violations of detente as the United States and Russia have known it, and largely practiced it, for six years? In the light of Nixon's official definition, the answer would have to be "No."

"The Soviet Union," he said, "will always act in its own self-interest, and so will the United States. Detente cannot change that. All we can hope from detente is that it will minimize confrontation in marginal areas and provide, at least, alternative possibilities in the major ones." Brezhnev has repeatedly confirmed this realistic interpretation of detente's limitations.

Nixon, in his memoirs, refers to the behavior of Russia during the 1973 Yom Kippur war. Critics of detente argued the agreement was a failure because Russia didn't warn the United States that war was about to break out. The former president, however, said it was not an example of the failure of detente, but rather "an illustration of its limitations - limitations of which i had always been keenly aware."

The Russians, from the beginning, showed how far they were willing to go in overlooking provocative U.S. actions as long as they were incidental to other objectives. In 1972, just before Nixon's scheduled arrival in Moscow to sanctify detente, the United States stepped up the war against North Vietnam, Russia's ally, by mining and bombing the harbor of Haiphong, hitting Soviet ships in the process.

It was instantly assumed that Brezhnev would call off the Nixon visit and thus kill detente at its birth. Instead, the Russians suppressed their natural resentment, took the attack in stride and went forward with the agreement that, with all its faults, is still prized by nearly all nations as the world's best safeguard against a nuclear holocaust.

If Brzezinski's comprehensive concept of detente were to prevail. Russia would have a longer list of complaints against the United States than the White House security adviser has against the Soviets, beginning with the Jackson-Vanik Amendment of 1974, the legislation that outlawed ordinary trade and credit relations with Moscow because of its Jewish-emigration policies.

This was seen as a direct blow against detente not only to Russia, but by Nixon and Henry Kissinger as well, for trade was part of the May 1972 agreement. Kissinger, by quiet diplomacy, had been abel to increase Jewish emigration from 8,000 to 36,000, and he begged Congress to let him continue, but it opted for force, with the result that emigration again dropped below 10,000.

As for Brzezinski's alarm over the Soviet military buildup, Gerald Ford, after leaving the White House, said it "is not sudden surge." He noted it had been a "long-range program," and, he added, "I don't necessarily think that buildup is for adventures around the world. It is my feeling that they are doing it because they feel it is necessary for their own security."

During the 1976 presidential campaign, however, detente became a political football, and Ford, under pressure from Ronald Reagan, backed off from his SALT II agreement with Brezhnev, and finally banished "detente" from his vocabulary, for which he was critized by Carter.

Nonetheless, Carter, in his first weeks as president, launched a surprise humanrights attack on Russia, invited a Soviet dissident to the White House and backed bigger transmitters for Radio Liberty and Radio Free Europe, which are seen by the Soviets as instruments for antiRussian propaganda.

French President Valery Giscard d'Estaing was prompted to say that Carter had "introduced a fresh ideological dimension" to his foreign policy. "It has," he unhappily noted, "compromised the process of detente." Other friendly leaders, such as Chancellor Helmut Schmidt of Germany, Canadian Prime Minister Pierre Trudeau, and even Edward Heath, former prime minister of Great Britain, have said much the same thing.

Both the United States and Russia could well heed David Owen, the British foreign minister, when he says: "It would be folly indeed for one side to make the process of detente so distasteful to the other that it would prefer to opt out altogether. The golden rule must be that neither side should pursue policies that so raise the level of confrontation that the structure of detente is itself threatened."