After the defection of two of the last remaining leaders of Cambodia's infamous Khmer Rouge guerrilla group, there is intensifying international debate over whether they should be brought to justice.

Several Western countries, including the United States and Britain, have said the pair, Khieu Samphan and Nuon Chea, should be put on trial for genocide.

The desire to see the perpetrators of Cambodia's notorious "killing fields" face justice for their crimes is understandable, not least among the many Cambodians who were victims of the Khmer Rouge's short but bloody period of misrule in the late 1970s.

But if calls for Khieu Samphan and Nuon Chea to stand trial do lead to action, it is likely that the investigation would unearth some uncomfortable truths for many in the international community.

Keeping the Khmer Rouge alive

China, the United States and several Southeast Asian countries were among those who, one way or another, kept the Khmer Rouge alive after an invading Vietnamese army, backed by the Soviet Union, drove them from power.

At the height of the cold war their strategy seemed expedient to combat the spread of communism, but it might prove less defensible today.

Thailand, Cambodia's western neighbour, funnelled weapons and supplies to the Khmer Rouge. Pol Pot and his senior colleagues crossed the border frequently and Thai businessmen helped the guerrillas dispose of their illegal logs and gems.

Last week Cambodian Prime Minister Hun Sen hinted broadly at Bangkok's role in sheltering Khmer Rouge leaders. The Thai Prime Minister, Chuan Leekpai, retorted that Cambodia was trying to pass the buck.

Thailand and probably others too would like to see any tribunal deal only with the years the Khmer Rouge were in power.