In great-power relations, the new year has opened with a subtle change in the relationships of China to the Soviet Union and to the United States. Peking has moved itself by a shrewd, calibrated half-step away from general hostility and back toward normalized relations with the Soviets.
The change at this moment, on the eve of the first exploratory and conceivably conciliatory meeting between the Soviets and Americans since Ronald Reagan entered the White House, is obviously intended to position China more flexibly in the triangle (Moscow-Peking-Washington) of the three powers.
No one can foresee whether the meeting in Geneva on Monday between the US and Soviet foreign ministers is going to lead to a lasting thaw in Soviet-US relations. But once Mr. Reagan sets his footsteps in that direction, anything can happen. In diplomatic quarters these days the most debated question is whether a second d'etente is on the horizon and how it would work.
If there is to be a second US-USSR d'etente, then China will want to be in easier relations with Moscow, because the closer Washington is to Moscow the less support Peking can expect from Washington against the Soviets. There is always the danger for the Chinese of Americans and Soviets getting too chummy for China's welfare.
China has been in a state of tension and at times of actual hostility with the Soviets since 1966. In that year ambassadors were recalled, embassies in Peking and Moscow were hemmed in by screaming mobs, and angry notes were exchanged. Things got worse in 1967 and much worse in 1968. In March of that year, Soviet and Chinese armies fought one battle on an island in the Ussuri River and another in August along the frontier between the Chinese province of Xinjiang and the Soviet Union.
As long as the United States was also in a condition of tension with the Soviets, China could afford to be in open hostility with Moscow. It could be reasonably certain that the US and USSR would not gang up against China.
But the triangular relationship was changed abruptly in early 1972 when then-President Richard Nixon went to Peking to reopen formal US-Chinese relations. He followed that up by going to Moscow and launching ``d'etente'' with the Soviets.
The Chinese began to soften their differences with the Soviets. There were again ambassadors in the two capitals. There was groping toward a resumption of normal relations.
That phase ended in early 1979 when the Chinese invaded Vietnam, which had become a satellite and dependency of the Soviet Union. The strain between China and the USSR got worse in December 1979, when the Soviets invaded Afghanistan.
In 1980, on April 10, the 30-year treaty of alliance which China had signed with the Soviets in 1950 expired. It was not renewed. It ended with no communication between the two governments. It had long since outlived its time.
But on April 20, 1980, a Chinese envoy arrived in Moscow. The two countries sounded each other out on talking about a possible restoration of normal relations. Those parleys got under way in 1982 and finally, on Dec. 28, 1984, achieved the signing of three agreements to put their trade and technology relations on a formalized basis.
The agreement set up a commission to supervise trade and scientific and technological exchanges. It provided for a 22 percent increase in barter trade for 1985. This presumes that the value of exchanges between the two will climb to $1.8 billion. US trade with China is now at $6 billion, and rising. The third agreement provided for increased student and scientific exchanges.
The trade agreement included a provision that the Soviets will help the Chinese in completing and modernizing some of the factories that were being built in China by Soviet engineers during the early period of the alliance. That had ended in 1960 when the Soviets pulled their technicians out of China and took the blueprints for the factories along with them.
But the Chinese made it clear by public assertion that the new three agreements on trade and technology do not constitute a resumption of full normal relations. They have three conditions that are not yet fulfilled: that Moscow reduce its military forces along the Chinese frontier, pull its troops out of Afghanistan, and cease from supporting Vietnam's invasion of Kampuchea (Cambodia).
So 1985 opens with the United States groping around the idea of improving its relations with the Soviets and with the Chinese getting themselves positioned to do more of the same if the Americans go along that road.
As things stand at the beginning of the year, the Chinese-American relationship remains the closest and friendliest within the triangle. The chances appear to be that this will continue to be true for some time. Their differences are minor, their common interests substantial. They have no unsatisfied territorial demands on each other. Neither is threatening anything considered important by the other.
In contrast, the Soviet-American relationship is burdened by an arms race, by Soviet domination of the satellite countries of Eastern Europe, by the Soviet invasion of Afghanistan, and by Soviet imperial activities in such places as Africa and Central America.
The Chinese-Soviet relationship is burdened by Soviet occupation of Asian territories which the Chinese claim; by the Soviet presence in Afghanistan and Vietnam; and by 52 Soviet Army divisions along the Chinese frontier backed by 135 SS-20 intermediate-range ballistic missiles and covered on the eastern flank by the Soviet Pacific fleet of 133 submarines as well as 88 major and 220 minor surface combat vessels.
It would be difficult for the Chinese to reach easy relations with the Soviets, which Reagan probably can do if he chooses. But insofar as they can, the Chinese intend to follow Reagan on the road to Moscow lest he gain the favorable position in the triangle of being able to play one off against the other.