By Michael Martina

BEIJING (Reuters) - The secret flight by blind Chinese activist Chen Guangcheng from smothering home detention to what appears to be U.S. protection conjures images of the last Chinese dissident to seek shelter with the U.S. mission in China - astrophysicist Fang Lizhi.

China and the United States have kept silent on Chen's whereabouts, but a U.S.-based rights group has told Reuters he is under U.S. protection and high-level talks regarding his status are under way.

If Chen is holed up with the United States - possibly at its Beijing embassy - it could open a wound in U.S.-China relations not unlike the rift more than two decades ago caused by Fang who, along with his wife, took refuge with the United States following the 1989 Tiananmen crackdown.

Like Chen, an activist who helped women who were victims of forced abortions, Fang was an outspoken critic of a different era of Beijing's human rights policies.

Fang emerged as an eloquent advocate of radical political change in China in 1986. He was quoted as saying in 1987 that the Chinese Communist Party could not boast of a single success in nearly 40 years of rule. "Marxism ... is like a worn dress that must be put aside," he said.

His constant challenge to the Communist Party apparently led China's former paramount leader, Deng Xiaoping, to single him out in a secret speech in 1987 for expulsion from the party.

In the wake of the June 4, 1989, crackdown on pro-democracy activists centered on Beijing's Tiananmen Square, Fang and his wife took refuge in the U.S. ambassador's residence after being accused of counter-revolutionary crimes, a charge tantamount to treason - which could have meant the death penalty.

Fang had no public role in the student-led protests, but sought shelter after government supporters burned effigies of him. His more than yearlong ordeal under U.S. protection enraged China and became a sore spot in bilateral relations.

It was June 1990 before Beijing, in a concession to Washington, allowed Fang to leave China with his wife to seek medical treatment abroad, saying the couple had shown "signs of repentance."

EMBASSY SUBTERFUGE

James Lilley, the U.S. ambassador to China who sheltered Fang and his wife, published colorful details of embassy subterfuge and high-stakes negotiations with the Chinese in an acclaimed 2004 memoir titled "China Hand."

Lilley described Fang as an "affable type," whose sense of humor helped get him through tense times. Lilley detailed absurd moments with Chinese authorities, who in October 1989 warned him "not to use Halloween as a ruse to sneak (Fang) out."

"The truth was Fang was a living symbol of our conflict with China over human rights," wrote Lilley, who died in 2009.

"The longer he and his wife remained under protective U.S. custody, the more difficult it would be to repair the considerable damage that had already been done," he wrote. Continued...