A business manager in Hanoi, Pham Hong Son, has spent 42 months in a Vietnamese prison. His crime: downloading an essay titled "What is Democracy?" from a U.S. State Department Web site, translating it and sending it to friends and senior Communist Party officials.

Son, 36, who worked for a pharmaceutical company, was convicted of espionage in Vietnam after a closed, one-day trial in June 2003. He was sentenced to 13 years, later reduced to five.

"What he did was legal," insisted his wife, Vu Thuy Ha, 34, in a June interview in Hanoi. She said that her husband was exercising free speech and did not commit a seditious act. "What can anyone do with the translation? What can they do to overthrow the government?"

Last week, the U.S. ambassador to Vietnam, Michael Marine, called on Vietnam to release Son and four others described as prisoners of conscience. Vietnam has made progress in "collective" human rights such as improving education and reducing poverty, Marine noted. But it is still intolerant of political dissent, he said.

"History has shown that political and religious freedoms go hand in hand with economic prosperity," Marine said in a speech to the American Chamber of Commerce in Hanoi. "The pace and scope of Vietnam's future success depends on a strong commitment to reform in both of these areas."

Political analysts and international human rights groups do not know precisely how many prisoners of conscience Vietnam has detained, but U.S. officials said the number of cases they have been able to verify had dwindled in recent years to 10 or fewer.

During the past year, Vietnam has released more than 26,000 prisoners, of whom perhaps 15 were political or religious prisoners, U.S. officials said. The younger ones in particular, such as Son and Nguyen Vu Binh, who was accused of posting "reactionary" articles on the Internet and of trying to set up a liberal democratic party, remain incarcerated.

The government insists it is not repressing religious or political rights. "Some people may argue that Vietnam does not have freedom and democracy and only has a one-party system. But you know, our ultimate goal is to maintain political stability and serve the interests of the people," Prime Minister Phan Van Khai said in a June interview. "We do not agree with arguments from the outside that there are prisoners of conscience in Vietnam. We do not have any prisoners of conscience in Vietnam."

Vietnam last month issued a human rights report in which it promised to respect freedom of expression and promote free use of the Internet. A revised press law in 1999 stated that citizens have the right to be informed, express opinions and provide information without being censored by any organization or individual, it noted.

Nonetheless, the United States last year placed Vietnam on a list of "countries of particular concern" with regard to religious freedom. Officials expect Secretary of State Condoleezza Rice to decide soon whether Vietnam should remain on the list. Marine said that although Vietnam has taken steps to expand religious and political space, "there is more, much more, that the authorities can and should do."

Pham Hong Son was part of a loose group of young men, including his friend Nguyen Vu Binh, who believed in expanded individual political freedoms. Their circle was not large enough to constitute a movement, according to interviews with several older dissidents. They rarely met in groups because to do so would invite government scrutiny.

The older dissidents said they warned the younger men to keep a low profile. Son, for instance, once thought of setting up a democracy fund, said Hoang Minh Chinh, 86, who over the decades has been imprisoned three times by the government for a total of 20 years.

"I told him that it was impossible to do that because the government would arrest him and give him a lot of trouble," recalled Chinh, who lives in a small house in the heart of town. "But he kept coming to visit me, and tried to persuade me to talk to my friends about the fund to get their support."

These dissident colleagues agreed that the fund was risky, and Son dropped the idea, Hoang said.

Then one day Son came to Chinh with a copy of the essay he had translated. He told Chinh he had given the U.S. ambassador, then Raymond Burghardt, the first copy as a gift. The second went to the general secretary of the Communist Party. The third went to Chinh.

Son also showed the translation to his wife, an administrative assistant for a nongovernmental organization. She liked the piece. Though she realized that the topic was "sensitive," she said, "at that time, I didn't know that it would be dangerous to my husband and my family. I think people have a right to do personal research. I don't understand why he had to be arrested."

Son also translated and sent to friends and officials an essay he wrote in French titled "Encouraging Signs of Democracy." Neither essay advocated violence, Vu Thuy Ha said. "He was trying to propose steps to improve democracy in Vietnam," she said.

On March 25, 2002, soon after Son sent the second essay, a special police unit came to their house, Ha said. The police seized Son's computer and personal papers and took him for questioning. Son published an open letter on the Internet protesting the search and confiscation of his belongings.

The next day, he visited Chinh. "I warned him, 'You're going to be arrested soon,' " Chinh recalled. "I advised him to try to tell the authorities that what he did was not illegal."

On March 27, the police took Son, without an arrest warrant. When Ha came home that evening, she found books, dishes and clothes knocked to the floor.

Ha and her sons now live with her parents. During a visit, the boys, 6 and 8, scampered about, playing tunes on an electronic keyboard and jumping on a bed.

The younger boy, Pham Vu Duy Tan, who has his father's bright eyes, said he missed his father. The older boy, Pham Vu Anh Quan, wanted to know why his father could not have a phone in prison. They asked when, exactly, he would come home.

Their father's release date, Ha told them, is March 27, 2007.