China's threat to carry out a punitive military strike against Vietnam ought to make the Carter administration reassess the pro-China, anti-Vietnam policy it has pursued since Zbigniew Brzezinski's trip to Peking last May.

The open threat voiced by Vice Premier Teng Hsiao-ping to punish Vietnam for its invasion of Cambodia coincides with a Chinese effort to achieve tighter coordination among Chinese, U.S. and Japanese policies toward the Soviet Union. U.S. analysts believe Peking hoped to pull the United States into a much tougher posture toward Vietnam and the Soviets in Asia by inflicting a visible military defeat on the Vietnamese. A key factor in the Chinese plan appears to have been the belief that the United States, although more cautious than China, shares the Chinese strategic view of the danger from an allegedly Soviet-dominated Vietnam.

The Carter administration has done nothing to disabuse the Chinese of that belief. While trying to persuade Teng not to invade Vietnam, U.S. officials have not challenged the Chinese thesis that Vietnam is the "junior partner" in a Soviet scheme for world hegemony -- the "Cuba of the Orient." But the accuracy of this interpretation is the crux of the issue for U.S. policy. A more detached view of Vietnam's foreign policy suggests a very different interpretation: that Hanoi has moved closer to the Soviets since 1975 not because of a decision to participate in a Sovietmade plan for Southeast Asia but because of its own perception that China was trying to force it to adhere to its global anti-Soviet line.

China's relations with Vietnam since 1975 have been dominated by a self-fulfilling prophecy.By treating Vietnam as having already sold out to the Soviets, China has pushed Vietnam several steps closer to the reality. Vietnam had not planned to join the Soviet economic bloc, but after the Sino-Vietnamese crisis in April and May 1978, when China began to withdraw its aid projects from Vietnam, Hanoi took that symbolic step of joining a Soviet-sponsored economic association. And Vietnam had resisted signing a Vietnam-Soviet friendship treaty, as suggested by Moscow from 1975 on, until last November, when a Chinese invasion had become a distinct possibility because of Vietnam's plans for Cambodia.

Even the Cambodian invasion, however wrongheaded and provocative of China, must be seen as the consequence of Vietnam's conviction that China was manipulating the Pol Pot regime to wage a border war to harass and weaken Vietnam. Vietnamese policy had been to resolve the border conflict with Cambodia by negotiations until 1978, when Hanoi began to view the Pol Pot regime as an instrument of Chinese policy. At that point Hanoi began to plan the overthrow of Pol Pot by any means possible, including military force.

The anti-Vietnamese bias in U.S. policy, first suggested by Brzezinski's endorsement of Chinese resistance to "regional hegemony" and confirmed by the refusal to normalize relations with Vietnam in 1978 while expressing "serious concern" over the Soviet-Vietnamese treaty, has further compounded the consequences of Chinese misperceptions of Vietnam. It has left Hanoi even more isolated and dependent upon the Soviets than they would otherwise have been.

The Vietnamese desire to avoid exclusive reliance on a single major power should not be underestimated. They have had too many unhappy experiences with the Soviets over the past quarter century to believe that their interests will not be sacrificed at Moscow's convenience. As Premier Pham Van Dong told an American delegation last August, "Whenever in our 4,000-year history Vietnam has been dependent on one large friend, it has been a disaster for us." Henry Kissinger acknowledged the primordial Vietnamese desire for some degree of balance in its relations with the great powers -- although he, too, spurned relations with Hanoi -- when he said in late 1975, "They need a third country to balance the Soviets and China.... They are banking on the United States being opposed to both."

Because of the policies of other powers as well as its own miscalculations and misperceptions, Vietnam now finds itself in its most serious crisis in decades, facing the threat of invasion from China, bogged down in a Cambodian war that will bleed it of resources and sap its morale, with a massive food deficit and politically isolated except for the Soviets and their allies. Vietnam's margin of maneuver has undoubtedly been reduced by the developments of the past year, and Soviet pressure for military advantages in Vietnam is likely to grow rather than diminish.

The Vietnamese believe the one thing that might bring the United States to realize its interest in supporting greater Vietnamese independence from Moscow is a fear of military base rights for the Soviets, and they apparently intend to play that card for all it is worth. Last November a high Vietnamese official, discussing the Sovietnamese Vietnamese friendship treaty, said to me, "We can go further, but we have exercised restraint." He said Vietnam had told the United States officially that it preferred to have reconciliation with the United States, but that if the United States refused, Vietnam would have to "make other decisions."

The implied threat to agree to farreaching military arrangements with Moscow may be a bluff. But it should not be forgotten that, in another crisis in the Hanoi government's history, only days before the outbreak of the war of resistance against France in 1946, Ho Chi Minh offered the use of Cam Ranh Bay as a naval base to the only country that he thought might be willing and able to give Vietnam some support against the French -- the United States.

It is a fundamental interest of the United States, as well as of all of Southeast Asia, that Vietnam maintain its independence from both China and the Soviet Union. That independence rests in turn on the maintenance of a balance in which the United States must play its part as a great power in Southeast Asia.The Carter administration will be committing a major strategic blunder if it fails to act -- and act quickly -- on that reality.