Ever since President Reagan met China's Prime Minister Zhao Ziyang at the North-South ''summit'' conference at Cancun last October (22-23), relations between Washington and Peking have been bristly and tense.
The Chinese have issued repeated warnings against the sale of United States weapons of any kind to Taiwan. Their propaganda apparatus has revived an old and long abandoned party line. As in the old days Peking now lumps the US together with the Soviet Union. It calls both of them imperialist.
Chinese criticism of the Soviet Union is livelier than of the US, but there is plenty of criticism of the US. It is obvious that the orders have gone down from on high in Peking to adopt an ''evenhanded'' attitude toward the two superpowers.
What is it all about?
When Richard Nixon and Henry Kissinger reopened US relations with mainland China in 1972 (after 20 years of hostility and no diplomatic communication) they took pains to do so without an overtone of hostility toward the Soviet Union. The two of them visited Peking, and stopped off in Moscow on their way home to fill the Soviets in on their talks in Peking.
The Nixon-Kissinger technique was to use the reopening of relations with Peking for bargaining power with the men in Moscow, but always and carefully in an ''evenhanded way.'' They sought easier relations with Moscow. They built ''detente'' with the Soviets on the foundation of the new US relations with China.
In those days every American visitor to China was treated to an eager dissertation by the top Chinese on the evils of the Soviet Union. The US was constantly ''warned'' about Soviet expansionism. The Chinese treated the Nixon-Kissinger people as innocents who needed a lesson in the evils of Soviet imperialism. The Soviets were denounced daily. The Americans were warned, and cultivated.
The operation worked to the American advantage. The US played the middle role. It treated the Soviets and the Chinese with equal care, courtesy, and coolness. It avoided special closeness to either. It also avoided open hostility toward either.
In other words, for the remainder of the Nixon presidency and into the Ford presidency, the US played the balance of power role between Peking and Moscow. Each wanted more from Washington than Washington wanted of either. The open hostility was between Peking and Moscow.
Things are different now. The Chinese no longer need to lecture Washington about the dangers of Soviet imperialism. President Reagan proclaims those dangers whenever the subject comes up. He outdoes the Chinese in saying critical things about the men of Moscow. He parades his hostility toward the Soviets. There has been talk around the White House of selling modern US weapons to the Chinese.
There was never the slightest thought back in the Kissinger-Nixon era of selling modern US weapons to the Chinese. The subject did not come up. The US was regularizing its relations with China and was willing to help China modernize its industry and its commerce. But it was not treating China as a potential military ally. Relations between Peking and Washington were excellent.
The Chinese probably wanted a personal report from their prime minister on his meeting with the President at Cancun before making any firm decision back in Peking about their relations with the new administration in Washington. The meeting took place at Cancun. Ever since the Chinese have been playing the role which had belonged to the US during the Nixon-Kissinger days.
The open and avowed hostility in these days is between Washington and Moscow. The Chinese have soft-pedaled their own hostility toward Moscow. They are now in the balancing position from which they can play Moscow off against Washington and vice versa. They are making demands on Washington instead of seeking help from Washington.
The Soviets were the beneficiaries of the 20 years of open hostility between the US and China. Moscow then held the balance of power. Washington benefited during the period of extreme Chinese-Soviet hostility. Now its China's turn. Mr. Reagan handed them the balancing position by his own revival of a state of declared hostility toward Moscow. The Chinese have grasped the opportunity - as any professional diplomat would expect them to do. That is how professionals play the game.