WHY DID Shen Tong go back to China? That was the question most asked by friends who called me from all over to express shock and regret when the evening news reported on Sept. 1 that Shen, a student leader of the 1989 pro-democracy movement, had been detained by the Beijing authorities. Subsequently he was charged with "engaging in illegal activities" for attempting to hold a press conference on human rights.

Shen Tong was one of the lucky few to escape Tiananmen Square and to reach the United States. Here, he had been enrolled as a graduate student in political philosophy at Boston University. Shen is not here to explain why he left his comfortable existence a month ago and risked returning. As I was Shen's voice for an autobiographical book that described his participation in the democracy movement, I take the liberty now to speak for him. I only hope that I can do him justice.

The last time I saw Shen was in New York in June. Over dinner at a French bistro in the theater district, he told me of his plan to return to China. Alarmed, I warned him about the probability of his arrest and imprisonment and worried aloud that he had nothing to gain and everything to lose. Very matter-of-factly, Shen told me of his need to go home.

For the last three years, Shen has fought for the memory of his friends who were crushed beneath the tanks in Tiananmen Square, and for his schoolmates who languish in Chinese prisons and labor camps. Yet he has lost nearly every battle with the Bush administration to bring pressure on the hardline Communists in Beijing. He has suffered one disappointment after another, from the granting of Most Favored Nation trade status to the president's New York meeting with Chinese Premier Li Peng -- one of the "Butchers of Beijing" responsible for the slaughter of innocent students and civilians. Shen could not reconcile the outpouring of genuine sympathy from the American people and the vocal support of prominent U.S. politicians -- from Sen. Jesse Helms to Sen. Edward Kennedy -- with the Bush administration's policy of tolerance and accommodation of the totalitarian Chinese government.

Unlike many other Chinese exiles who are prepared to put the horror of Tiananmen Square behind them and begin life anew in the United States, Shen was obsessed with going back. Before enrolling at Boston University, he asked me often what he ought to study in order to contribute best to the building of a democratic China. And unlike some of the once-prominent student leaders who have abandoned the democracy movement in search of personal gain in this country of opportunity, Shen Tong continued to agitate for change through the Democracy for China Fund, an organization he founded in 1990. I hope he won't mind my telling that American volunteers at the Fund nicknamed him "Bonehead," a playful tribute to his stubborn resolve.

In the end, his studies seemed to him utterly irrelevant and his pro-democracy work here ineffective. While he waged futile battles, his best friends, young men who spent three years studying, socializing and philosophizing about democracy in cramped dormitory rooms with him at Beijing University, were living an unspeakable hell in the Chinese gulag. Last week, the human rights organization Asian Watch confirmed the authenticity of a letter smuggled out of Lingyuan Prison that graphically details the physical tortures visited upon the pro-democracy students who steadfastly refuse to denounce the movement. For resisting indoctrination, the student prisoners regularly suffer beatings and electric shock torture with 5,000-volt batons, and are forced into slave labor for 12 hours each day.

It was clear back in June, and even in the pleasant surroundings of a Manhattan restaurant, that Shen Tong was consumed by feelings of guilt and impotence. At last, he succumbed to those feelings. In a letter given to a friend shortly before his arrest, Shen Tong wrote: "I returned to stand again with those I left behind." His bonds with imprisoned student leaders like Wang Dan and Liu Gang were forged in the Democracy Salons of Beijing University and seared by the bloody massacre in Tiananmen Square. I suppose it was inevitable that he would feel compelled to join his comrades in their suffering.

There are those who question the timing of his return, speculating that in a year when the president is preoccupied with re-election no concerted action will be taken to help secure his release. But even were it not an election year, I doubt Shen would have felt any assurance that the Bush administration would act swiftly and decisively on his behalf. It just has not been his experience that when it comes to China, the United States government would do the right thing.

Not to be forgotten in this drama is Shen Tong's mother. When I first met her in Beijing in July of 1990, she had expressed terribly mixed feelings about her son's exile. Her husband, Shen's father, had died of cancer one month after the Tiananmen massacre and Shen's escape. She was resigned to the likelihood of not seeing her son again for a very long time but, at the same time, was relieved that he had escaped the persecution that followed the crackdown. Her joy in her only son's homecoming must have been tempered by great apprehension and was, in the end, fleeting.

Shen Tong has come a long way since he first stepped off a plane in Boston three years ago. He has learned to speak flawless English, to appreciate American humor and to indulge occasionally in that great American pastime -- video games. But I am glad that our egocentric culture has not changed what he is -- a thoughtful and patriotic Chinese.

In the preface to his book, Shen Tong wrote: "In this great international family that I now live in, there is only one door that remains closed to me -- the door that leads to my native country, China. The story I want to tell is the story that lies behind the closed door. There is my childhood, the silent Changan Avenue that holds our history and our future. There is my family, that splendid earth, and my people. There is my dream and my friends who wait in prison for that dream to come true."

Having attempted to explain Shen Tong's motives on his behalf, I must confess that I still do not fully understand how something as abstract and ambitious as "democracy in China" could compel a young man with a bright future to surrender his freedom in exchange. I am still torn, as I know others must be, whether to view his return to China as an act of courage or an act of foolishness. I suppose that is because I am only a writer. Shen Tong is a dreamer and an idealist; he has brashness and daring -- the stuff that revolutionaries are made of.

Marianne Yen is the co-author of "Almost A Revolution," the story of Shen Tong's boyhood and leadership in Tiananmen Square.