Former President Richard Nixon's visit to China combines nostalgia with an as yet unrealized hope.
The nostalgia is for the Nixon administration's most dramatic foreign policy success - the opening to China that resulted in the first visit of an American president in office to China. That opening ended more than two decades of active hostility between Washington and Peking.
The hope, in Mr. Nixon's words, is that ''our two peoples (Chinese and American), by working together, can change the course of history.''
Nixon's visit coincides with the 12th congress of the Chinese Communist Party , which, according to Nixon, ''has declared a significant and new direction for the party and state.''
It is hoped this direction - one of pragmatic economic reforms and of a rejuvenated leadership - will achieve China's modernization by the end of this century. Because it means an open-door policy of economic cooperation with Western countries, China's ties with the United States should also be strengthened and become more varied.
These are as yet but hopes, and both Chairman Hu Yaobang and veterans like Politburo member Chen Yun have stressed the obstacles that bestrew the way. Nevertheless, the China of today would have been difficult to imagine 10 years ago when Nixon and the late Premier Chou En-lai signed the Shanghai communique reestablishing ties between the US and China and opening the way to full diplomatic relations achieved during Jimmy Carter's presidency at the end of 1978.
Mao Tse-tung's memory is still venerated, but much of his legacy has been dismantled with changes in the structures of China's two ruling institutions - the Communist Party and the state.
The post of chairman of the party, established and assumed by Mao in 1945, has just been abolished and Chairman Hu will step down to the position of general secretary. If, as is expected, the National People's Congress (China's legislature) passes a new state constitution in November, only one chairman will remain - the chief of state.
The Chinese Communist Party will still lead the government, but members and leaders alike have been told that the party must operate within the framework of the state - it cannot stand above the law.
No one can predict with certainty that another personality cult similar to the one that deified Mao will not arise again in China. But the 12th congress has taken every measure possible within the context of the communist ideology and system of government to ensure that collective leadership will prevail.
It is ironic that, in 1971 and 1972, only Mao's own overwhelming prestige and the universal respect in which Premier Chou was held could have achieved the 180 -degree change in policy required for China to respond to Nixon's gesture.
Today and in the future, Sino-American ties will have to depend on the solid national interests of both nations, not merely on the pronouncements of charismatic individuals.
Also, in the past and even today, mutual opposition to what is perceived as the common threat of Soviet expansionism has been a powerful ingredient in the Sino-American relationship.
But as Nixon said in a toast at his welcoming banquet, ''Even if there were no Soviet Union, it would be a tragedy of history for our two great peoples not to work together, trade together, consult together, and build together.''
Recently, Washington and Peking averted what could have been a showdown in their relationship by working out a compromise over American arms sales to Taiwan. The issue has not been finally resolved. But Sino-American relations are back on the track of normalcy.
This in turn made possible Nixon's visit at this time. The Chinese leadership treated the former president with extraordinary courtesy. Despite their preoccupation with the 12th congress, all three of China's top leaders met Nixon - Vice-Chairman Deng Xiaoping, Chairman Hu, and Premier Zhao Ziyang.
As one Chinese said, ''We know that in your country Nixon has been heavily criticized for having committed errors. But here in China, we have a saying: 'When you drink water remember the person who dug the well.' Mr. Nixon is the one who laid the foundation of the ties we have with America today. And we will always honor him for that.''