AT DAWN ON Tuesday, a few hours before Americans began voting, Sudanese police and soldiers arrived at a camp for displaced people in South Darfur. They set fire to huts, beat people with truncheons and shot an unknown number; then, as The Post's Emily Wax reported, they loaded 250 families into trucks and drove them away. They did all this, moreover, at a camp just eight miles from a contingent of Nigerian cease-fire monitors, whose job is supposedly to deter such war crimes. Meanwhile the United States is leading an international response to Darfur's crisis. Its principal goal is to deploy more African Union monitors of the sort that failed Tuesday.

For a while over the summer, the world's response to Darfur seemed to be gathering momentum. A series of high-level visits to the region, including stops by Secretary of State Colin L. Powell and U.N. Secretary General Kofi Annan, put pressure on Sudan's government to stop murdering civilians; the U.N. Security Council passed two resolutions condemning the abuses; Congress and then the Bush administration determined that the systematic killing of ethnic Africans met the definition of genocide. Sudan's government responded by allowing relief workers to bring food and medicine to displaced people and by agreeing to the presence of African Union troops. All this progress was unforgivably slow, and tens of thousands of people died waiting for it. But it was still progress.

Now the momentum has fizzled. Preparations for an African Union force continue, but the violence in Darfur has flared to the point that it's not clear what 3,500 outsiders can accomplish in an area the size of France. Tuesday's attack on civilians was just one of many, and anti-government rebel groups are growing more violent and numerous. From Bosnia to Sierra Leone, the world has a painful history of putting peacekeepers into situations where there is no peace to be kept. Darfur may be one more.

The world faces a choice now, and its nature must not be obscured by more weeks of U.N.-speak about being preoccupied with the problem. Having recognized weeks ago that the killings in Darfur represent genocide and having correctly projected that the death toll will amount to at least 300,000, the Bush administration and its allies must decide how much they care. They can choose to think beyond their flimsy African Union deployment. Or they can choose to accept genocide.