There was one name that top Chinese leaders alluded to repeatedly as they welcomed U.S. officials Wednesday to a high-level Beijing meeting, now overshadowed by the plight of blind activist lawyer Chen Guangcheng.

It wasn’t Chen. It was Richard Nixon, who 40 years ago became the first U.S. president to visit China, a trip that became a seminal moment in international affairs.

“Today, 40 years on, China-U.S. relations have grown well beyond what people could’ve imagined at the time,” said President Hu Jintao.

Indeed, by Thursday morning, when the dissident Chen appeared to have changed his mind about staying in China after U.S. officials negotiated a deal with the Chinese to protect his safety, the dynamic between the United States and China had entered a critical juncture, the outcome of which could reverberate for years.

“I know of no other arrangement that has ever been done like this in diplomacy with China,” a senior official said.

Each turn in the Chen narrative this week seems to reveal some new complexity or mystery about U.S.-China relations.

There is the issue of whether the negotiations between the United States and China over the fate of Chen are evidence that the two countries now have a stronger relationship than before — so strong that they can talk honestly about a sensitive topic such as human rights.

Senior State Department officials have insisted that the talks on the deal were “extremely intense but collaborative.”

“The dialogue was conducted in a way that was consistent with a strong relationship between the two sides,” said one senior official within hours of accompanying Chen from the U.S. Embassy, where he had sought refuge, to a hospital in central Beijing.

Some are worried, however, that this risky test of the relationship’s strength may have failed.

Many activists are suggesting that the Americans made the critical mistake of trusting the Chinese government too much, given its history of mistreating the country’s dissidents and not enforcing the rule of law. In other words, U.S. diplomats overestimated the quality of their relationship with the Chinese.

The first sign of trouble came when, following Chen’s trip from the embassy to the hospital, the Chinese government broadcast tough critiques of the United States’ actions through its state-controlled news outlets. The tough talk suggested that China did not feel nearly as positive about the talks as U.S. officials did.

Some experts have pointed out that while the relationship between the United States and China has matured some over time, deep distrust remains between the countries.

A recent Brookings Institution paper co-authored by Wang Jisi, a prominent international affairs writer in China, argues the Chinese are still deeply suspicious of the United States, especially when Americans seek to promote democracy and human rights. The Chinese government often perceives these efforts as meant to “divide and weaken China,” part of a U.S. goal of blocking China’s rise as a global power.

The Chinese may be especially mistrustful of the United States at this moment, when the country’s political order is experiencing turmoil not seen since the Tiananmen Square massacre in 1989. The upheaval was triggered by a scandal engulfing erstwhile rising Communist Party leader Bo Xilai, whose wife has been accused of murdering a British businessman. The episode, which dominated headlines until Chen’s story displaced it, showed cracks in the party’s monolithic image.

The timing of Chen’s escape from de facto house arrest in Shandong province, plus the subsequent U.S. admission that it helped him enter the embassy in Beijing, could have deepened suspicion among party leaders that the Americans sought to embarrass the Chinese government just as it was showing some weakness.

This suggests that instead of meeting with willing partners in the Communist Party, the Americans were negotiating with officials who had no intention of assisting Chen or the United States in their campaign to promote human rights.

Some human rights watchers see proof of this already, with reports that the Chinese have rounded up many of Chen’s associates, who now cannot be contacted.

If the United States indeed placed too much faith in the Chinese government’s promises, then the incident could roll back years of progress in building trust on a host of other issues, including the economy and national security.

At no point have U.S. officials this week indicated publicly that they had any doubts about Chinese cooperation.

On Thursday, U.S. Ambassador Gary Locke described back-and-forth negotiations earlier this week in which the Chinese and Americans discussed highly detailed options for Chen that would have required enormous cooperation from the Chinese with questionable upside for them. He did not express any skepticism about the Chinese government’s willingness to follow through on its promises.

State Department officials, for their part, backed away Thursday from their attempts a day earlier to portray their assistance of Chen as a human rights victory. Less than 24 hours after Chen’s trip to the hospital, State Department officials were trying to paint the U.S. role as merely that of an interlocutor and go-between for Chen and the Chinese government.