IN EAST TIMOR, the Indonesian military has armed and nurtured private militias that, according to an on-site report from The Post's Keith Richburg, are now preparing for war. This is alarming news, calling for a strong response from the United States and other friends of Indonesia. The people of East Timor finally have a chance, a quarter-century late, to determine their own future. Indonesia's armed forces must not be permitted to spoil that.

A former Portuguese colony lying off Australia's northern coast, East Timor was brutally recolonized by Indonesia in the mid-1970s. More than 200,000 of its population of 700,000 perished in subsequent years in massacres or from war-induced famine and disease. With the passing of the Suharto dictatorship last year, Indonesia finally agreed to a U.N.-supervised referendum in which the people of East Timor could choose between independence and continued association with Southeast Asia's most populous country.

That vote is set for Monday, but the lead-up to it has not been smooth. Militias, tolerated and encouraged by the Indonesian military, have terrorized the civilian population, forcing thousands from their homes and killing and wounding many. Even U.N. workers have been threatened and attacked.

This campaign is intended to intimidate people from voting, or from voting for independence. Most onlookers believe the popular desire for separation is so strong that the intimidation will not succeed on voting day. But there is a grave danger that the militias will greet a pro-independence result with more violence. Indonesia has the power to prevent such a bloodbath, but does it have the will? The U.S. government should make clear that everything Indonesia hopes for from its allies -- loans and aid first of all -- depends on a fair vote Monday, and on respect for the outcome in subsequent days. If an international peacekeeping force is needed, the United Nations should be ready to respond.