After days of diplomatic tumult triggered by the plight of Chen Guangcheng, the dissident lawyer who fled house arrest to find temporary sanctuary at the U.S. Embassy in Beijing, China and the United States are now in an uncomfortable but familiar place — struggling to contain an unforeseen upheaval that, like many others since Richard Nixon met Mao Zedong in 1972, has soured but is not expected to shatter a relationship each country considers too important to fail.

When Hillary Rodham Clinton first traveled to Asia as secretary of state three years ago, she indicated that she looked forward to a new era of cooperation with China undisturbed by stale debates about jailed dissidents, Tibetan monks and other reported victims of persecution.

“We pretty much know what they are going to say” on human rights, Clinton said. “We have to continue to press them. But our pressing on those issues can’t interfere” with vital security and economic issues.

But just as the Tiananmen Square massacre in 1989 froze President George H.W. Bush’s plans for Sino-American comity, the travails of Chen, the blind lawyer, have now punctured what human rights campaigners deride as the Obama administration’s “illusions” about China’s ruling Communist Party.

“This is a moment of truth,” said Bob Fu, a Chinese exile who heads ChinaAid, a Texas-based Christian group that helped engineer Chen’s escape on April 22 from house arrest in Shandong province.

“China is not trustworthy and cannot keep its promises from one day to the next,” Fu added, referring to complaints that Chinese authorities have already reneged on assurances that Chen would be left in peace and allowed unfettered visits by American diplomats once he left the U.S. Embassy.

U.S. diplomats have been barred since Thursday from visiting Chen in the hospital, although an embassy doctor was able to see him Friday. Chinese security agents have thronged the ward where he is being treated for a broken foot suffered during his escape and a previous stomach ailment. Chen, who originally insisted he did not want to leave China, now says he wants to fly to the United States, preferably with Clinton, who was in Beijing for an annual round of high-level strategic and economic talks and was due to leave Saturday.

China — the United States’ biggest creditor, with holdings of Treasury bonds worth about $1.2 trillion — also appears to feel let down. It angrily accused the United States of violating unspecified international laws and interfering in China’s internal affairs by granting Chen entry “via abnormal means” to the U.S. Embassy in Beijing. It also demanded an apology, a demand that U.S. officials have rejected but which is part of what, over the years, has become a familiar ritual of Sino-U.S. crises. China also demanded — and didn’t get — an apology after one of its military jets collided with a U.S. Navy reconnaissance plane off the coast of southern China in 2001, an incident that badly dented, but didn’t upend, relations.

As in the past, both sides seem eager to limit the scope of the current fracas, though each is crimped by domestic politics ahead of a U.S. presidential election in November and a once-in-a-decade leadership transition due around the same time in Beijing.

Chinese leaders don’t have to worry about voters but do need to deflect accusations of being soft on foreigners, a frequent refrain among neo-Maoist nationalists, who have been particularly agitated since the ouster in March of one of their idols, Chongqing’s populist Communist Party boss Bo Xilai.

Chinese microblogs and Web sites have frothed with debate in recent days over whether Chen is a tragic hero or a foolish traitor. Much of it is coded, because Chen’s name is banned for online searches, as is the phrase “left of his own volition,” the official description of Chen’s departure Wednesday from the U.S. Embassy.

The Obama administration is also under pressure, with speakers at a congressional hearing on Chen’s ordeal Thursday demanding a wholesale rethinking of relations with China.

“America missed an opportunity in Tiananmen. Will this administration, too, fail to seize a historic moment?” said Rep. Frank R. Wolf (R-Va.) at the emergency meeting of the Congressional-Executive Commission on China.Wolf said he would request to see “all cable traffic, classified or otherwise,” relating to negotiations between U.S. and Chinese officials on Chen’s fate.

Others demanded that human rights be accorded the same central place in Sino-American diplomacy as they were in the United States’ discussions with the Soviet Union during the Cold War.

Soviet parallels are deeply alarming to Chinese leaders, who have closely studied the collapse of the Soviet Communist Party and are determined to avoid going the same way. One key lesson they have drawn is that China must avoid getting locked into formal discussions on human rights, as Soviet officials did after the signing of the so-called Helsinki Accords in 1975. Soviet dissidents used the accords to pry concessions from the party and rally foreign support.

The Soviet experience also taught Chinese party leaders that the most effective way to deal with troublesome dissidents is to send them abroad, a solution pioneered by Moscow in 1974 when it exiled Alexander Solzhenitsyn, author of “The Gulag Archipelago.”Solzhenitsyn, bundled onto a plane to Germany against his will, spent much of the next 20 years as a virtual recluse in Vermont.

China’s own exiled dissidents have mostly faded into obscurity, and Cheng Li, an expert on Chinese politics at the Brookings Institution in Washington, noted that it would be “very risky” for China to let Chen remain. “It’s like a time bomb to let him stay,” he said. “Previously they preferred to send such dissidents abroad, where they often become marginalized.”

Zhu Feng, deputy director of the Center for International and Strategic Studies at Peking University, said he didn’t expect any serious long-term damage from the crisis triggered by Chen.

“China’s relationship with the U.S. has reached a point where neither is simply defined as a friend or an enemy,” he said. “The fact that the two governments could close the door and talk about Chen for two days proves that no one wants a clash, no one wants escalation.”

Speaking Friday after talks in the Great Hall of the People with Vice Premier Li Keqiang, Treasury Secretary Timothy Geithner extolled “the very good progress of the last few days.” In an earlier meeting with Communist Party chief Hu Jintao, he hailed as “very promising” moves by China toward a more market-orientated exchange rate. Allegations that China manipulates its currency to boost exports has been a serious source of friction.

In opening remarks ahead of meetings in Beijing, Clinton did not mention Chen by name but referred obliquely to his case, telling Hu and other senior Chinese officials that they cannot deny the “aspirations” of their citizens “for dignity and the rule of law.”

Hu, for his part, warned that a deterioration in relations between the world’s two biggest economies would pose “grave” risks for the world. He made no mention in public of any need for an American apology.

After the meeting concluded Friday, State Councilor Dai Bingguo, a senior foreign policy adviser to the Communist Party, made clear that Beijing will give no ground on human rights. He reiterated China’s long-standing position that economic progress is the most important basic right and one for which the party has amply provided. While human rights came up during this week’s talks, he said, Washington and Beijing remain far apart.

“On this issue we still have fundamental differences,” Dai said, warning that “human rights should not be a disturbance for state-to-state relations” and “should not be used to interfere in the affairs of other countries.”

Clinton restated Washington’s position: “The United States continues to raise human rights because we believe they are essential for every country to uphold, and we raise specific matters of individuals and situations whenever necessary.”

But she, too, stressed the importance of not allowing disagreements to damage overall relations. “You have to look at the trend lines, not just the headlines,” she said.

Staff writer William Wan in Washington and researcher Liu Liu in Beijing contributed to this report.