Eight years after the fall of Saigon (now Ho Chi Minh City), Vietnam's ''Gulag Archipelago'' remains a controversial target for human rights activists. Vietnam's security forces remain committed to contain - by imprisonment, if necessary - what are seen as present or potential security risks.
These include both anti-communists and others who may resent what they see as a dominance of the south by northerners since re-unification after the Vietnam war.
In fact, many of the thousands sent to ''re-education camps'' for labor and indoctrination have been sent not simply for past acts - but as a precaution against any future opposition.
This is a kind of ''preventive detention,'' says Douglas Pike, director of the Indochina studies project at the University of California, Berkeley.
''Many had been National Assembly members, educators, and religious or village leaders. They were the 'loose cannon on deck', the people who might gain influence in the future.''
The Vietnamese communists appear to have hoped that systematic indoctrination under pressure would neutralize future opposition. ''The Communist Party has great faith in its ability to persuade people to see things its way,'' he notes.
There is still no clear sign that Vietnam is prepared to deliver on a trial balloon floated by officials late last year. That was to release some of the thousands of southern Vietnamese prisoners so that they can continue their ''re-education'' at home under supervision of mass organizations.
The delay of this move has set back what are seen as two objectives for Vietnamese leaders: to reduce the cost of maintaining these camps and to soften the criticism of outside human rights activists.
One problem: The longer prisoners are interned, the more embittered they may become, thus making them a greater risk if they are eventually released. But Vietnamese officials continue to argue that they are gradually reducing the number of prisoners.
Justice Minister Phan Hien said in May there are only 10,000 prisoners in ''re-education camps'' - compared to a figure of 16,000 cited last summer by Foreign Minister Nguyen Co Thach. From 1980 to 1982 Vietnamese officials used the figure 22,000.
The United States maintains that the number held in the camps is much higher. It sometimes uses the number 50,000, although a spokesman says that figure may be conservative.
The London-based human rights organization Amnesty International concludes that since the end of the war, those sent for ''re-education'' have included another group besides the government officers, political figures, and army and police officials of South Vietnam imprisoned soon after 1975.
The new group includes professionals, writers, artists, journalists, and community leaders held for expression of their views, Amnesty noted.
It reports that among these were the popular artist and cartoonist Choe (Nguyen Hai Chi), now held without trial for seven years, writers Nguyen Van Khanh and Nguyen Thanh Chieu, and medical researcher Dr. Nguyen Dan Que.
Amnesty, like other observers, has pointed out that the thousands sent to ''re-education'' camps have for the most part never been formally charged or tried in court. The foreign minister made a familiar defense of this in comments to four retired US diplomats who vistited Vietnam in February.
''Ninety percent of the people in re-education camps were guilty of capital offenses, and therefore the government was showing mercy by not putting them on trial,'' the foreign minister was quoted as saying.
Mr. Pike distinguishes those sent to ''re-education camps'' from those former members of the South Vietnamese security police who were executed or worked to death on special projects, including mine clearing operations.
''Often no charges were made. You could not tell if someone was sent to a camp because of something he had done or something the government thought he might do in the future,'' says one Vietnamese whose father died while a prisoner in a ''re-education camp.''
''I never could find out what my father was accused of,'' he adds.