Weinberger's Peking trip: new stage in US-China relations?

Secretary of Defense Caspar Weinberger's visit to China highlights an upturn in US-China relations after three years of deterioration. If successful, it should help to restore a significant dialogue between Washington and Peking. However, success requires modest goals and a recognition that a new political dynamic is at work in East Asia.

The Chinese have recently adopted a new international posture, positioning themselves between the two superpowers. Since last year they have cautiously explored the possibilities for limited detente with the Soviet Union. Four months ago they also decided to try to repair strained ties with the United States. Today, for the first time since 1949, they are attempting to improve relations with both superpowers.

This shift is based on two crucial considerations: (1) recognition that China's priority goal must be economic development, which requires a ''peaceful international environment'' and (2) the conclusion that China now should try to enhance its security by flexibility and maneuver among the powers. The shift makes obsolete one of the premises that motivated both Chinese and American leaders throughout the 1970s: that some kind of tacit US-China military-security alignment against the Soviet Union was both possible and desirable.

The Chinese leaders still see the Russians as the main potential threat to China's security, but they have downgraded the imminence of military danger and are trying to defuse the Soviet threat by political means. Already there are some signs of improvement in Sino-Soviet relations. The improvement is, and will remain, limited; there is no prospect of a broad rapprochement. Nevertheless, a limited detente is likely to reduce the confrontational nature of Sino-Soviet relations.

Until recently, the trend in Sino-American relations was very disturbing. From 1980 on, ties steadily deteriorated because of Peking's dissatisfaction with US policy toward Taiwan. In 1982, China exerted strong pressures on Washington to end all arms sales to Taiwan, and it came close to downgrading diplomatic ties.

Finally a compromise was reached in August 1982, by which the US government agreed to limit, and gradually reduce, arms sales to Taiwan. However, although this checked, it did not end, the deterioration in relations, which reached a new low early this year.

Then, in May, the Reagan administration decided to liberalize policy on technology sales to China. Peking viewed this as a major new sign of a desire on Washington's part to repair Sino-American relations, and since then the Chinese have shown increasing flexibility and a new willingness to compromise on many of the issues complicating relations.

In the context of developments since May, the Weinberger visit provides an important new opportunity to reestablish a high-level dialogue between American and Chinese leaders, which could then be advanced further when Foreign Minister Wu Xueqian visits Washington in October. If these two visits are ''successful,'' Premier Zhao Ziyang might then accept the invitation extended to him earlier this year, and if he does, President Reagan should consider a visit to China in 1984. A series of visits of this kind could establish a new basis for strengthening US-Chinese relations.

The prime requirement for Mr. Weinberger's visit to be a ''success'' is that his goals be modest. Accepting the shift that has occurred in China's foreign policy posture, the US now must operate on the premise that Sino-Soviet relations may improve, but that, even if they do, strong bilateral US-China ties - mainly political and economic rather than military - are important to both countries, strategically as well as in other respects.

Weinberger will doubtless have a broad-ranging exchange of views with the Chinese on global problems, to clarify where we still have parallel strategic interests and policies and where we still differ significantly. However, there is no necessity for him to make dramatic new proposals in the field of arms sales or military cooperation. In fact, under existing circumstances, proposals of this sort would probably be counterproductive.

The main objective of Weinberger's visit should be to increase the level of mutual trust between Washington and Peking, which is still relatively low. It is essential that he convince China's leaders (1) that the US will, as promised, carry out the commitments made in August 1982 to limit and reduce US arms sales to Taiwan; and (2) that the recent changes in US policy on technology sales to China will produce significant results. On both scores, Chinese leaders remain skeptical today.