John Pomfret, a former Beijing bureau chief for The Post, is writing a book on the history of interactions between Americans and Chinese.

The past two months in China have revealed something profound about the outsized expectations that China and the United States have for each other and the often-feeble returns on what many call the most important bilateral relationship in the world.

Many Chinese place the United States on a pedestal that looms even higher from the capital of a nation facing a deep crisis in belief. The Chinese vest the United States with a moral authority that Americans are flattered by but are often loath to accept. For its part, the United States, in need of a hand around the globe, wants China to start acting like a superpower. But the Chinese — for tactical reasons or otherwise — reject the responsibilities inherent in big-power status even as they, too, are beguiled by the attention.

Ever since aggressive young U.S. merchants first washed up on China’s shores and earned the sobriquet “the new people,” the two sides have expected great things from each other. But over the 229 years that Americans and Chinese have interacted, they have rarely been satisfied. And yet irrationally, almost magnetically, they keep coming back to each other for more.

The current cycle began in February, when the first of two very different Chinese men sought shelter in a U.S. diplomatic outpost. The first one, Wang Lijun, is a policeman famed for his brutality but also known as someone who had run afoul of his political godfather — once one of the most powerful men in China, Bo Xilai. On Feb. 6, Wang left Chongqing, where he had overseen a reign of terror against Bo’s enemies, and drove 200 miles to the U.S. Consulate in Chengdu. There, Wang requested protection because he feared for his life. He apparently had been investigating Bo’s wife in connection with the murder of a British businessman. The upshot of Wang’s day-long stay in the consulate sent shock waves through China’s political hierarchy. Bo was purged from the party. His wife, Gu Kailai, was arrested. And the Americans handed Wang back to the Chinese.

Why did Wang seek U.S. help after laboring for years in the belly of a system that, according to its internal documents and even some public speeches, views the United States as an “enemy”? For the same reason that many of China’s leaders park their children in U.S. universities and their money in U.S. real estate. Political correctness in China disallows expressions of admiration, affection, respect and unity of purpose with the United States; officials make them at their peril. But these constraints mask a more complicated reality. Chinese remain moved by America. So while apparatchiks toe the party line, privately they still want their children at Harvard, cluck at an American-born grandson (as did China’s late paramount leader Deng Xiao­ping) or run — when there’s no place to hide — to the U.S. Consulate.

Predictably, Wang was not granted any form of protection. But his gambit might have saved his life, and it definitely altered the course of China’s upcoming political transition. When U.S. officials handed Wang back, they gave him to an official of the Ministry of State Security from Beijing. If Wang had stayed in Chongqing, chances are he would have died with his story.

Then there is the tale of the second man. For years, Chen Guangcheng has been on the receiving end of the attention of men like Wang Lijun. Chen is a blind lawyer who has represented clients forcibly sterilized by officials carrying out China’s one-child policy. For those “crimes,” he has been jailed, kidnapped and beaten. He was released from prison in September 2010, only to be held in Shandong province by a team of police and local thugs in a makeshift jail. There were no charges against him, but that did not matter. The security services in China are all-powerful; their budget is bigger than that of China’s military.

Last month Chen escaped and made his way to Beijing. Where was the safest place for a human rights lawyer on the lam from a gang of toughs? And who could best guarantee his security in China going forward? Again the answer was a U.S. diplomatic facility.

The he-said, she-said of the negotiations between China and the United States over Chen’s fate are still being reported. Did U.S. officials rush the talks so they would not interfere with the annual economic and trade talks opening this week in Beijing?

That forum, by the way, is a testimony to the exaggerated U.S. expectations for China. By grouping hundreds of officials from the bureaucracies of both sides, it seems more like an exercise to convince China of its importance than a meeting with any practical utility. Did U.S. officials somehow apologize to the Chinese — an act that the Beijing government demanded publicly but that would privately sadden many of those same officials?

One thing is clear. Once Chen left the U.S. Embassy to seek medical treatment, he had second thoughts. Perhaps he should have requested asylum, he told reporters. Despite a deal that he would be protected from the goons who have menaced his family, he is on his own if he ends up staying in his own country. Kurt Campbell, the State Department’s point man on Asia, told reporters that an incident such as Chen’s would not happen again, but given Chinese expectations about America, that seems hard to guarantee.