THE MORAL ORDER we inhabit fell into focus on Thursday, and it was an awful moment. In an act without precedent since the U.N. Genocide Convention was adopted in 1948, a government accused a sitting counterpart of genocide -- a genocide, moreover, that even now is continuing. And yet the accused government may not pay a price for committing this worst of all humanitarian crimes, because there is a limit to how much powerful nations care.

Secretary of State Colin L. Powell, who leveled the accusation of genocide against Sudan's government, is to be commended for his honesty. During the Rwandan genocide in 1994, the Clinton administration initially shrank from using the word lest it compel a risky intervention. Mr. Powell, by contrast, dispatched a team of expert investigators to interview Sudan's victims; they were careful to collect only first-person accounts and to conduct a sufficiently large survey on which to base a strong conclusion. Of 1,136 people interviewed, a third had heard racial epithets while being attacked, and three-quarters had seen government insignia on the uniforms of their attackers. The culpability of Sudan's government, along with its racial motive, seems beyond doubt. Aerial photographs of Darfur, the western Sudanese territory that is the scene of the killing, show the selective destruction of ethnic-African villages. Numerous reports from journalists and human rights observers reinforce the verdict that the Arab-led government has been waging a war of ethnic extermination.

And yet, having spoken the truth about Sudan's barbarity, Mr. Powell offered little hope of ending it. "No new action is dictated by this determination," he told a Senate hearing on Thursday; the administration will continue to press other countries to press the United Nations to press Sudan's government. The uncertainty of this strategy was immediately apparent after Mr. Powell spoke. Brushing aside the evidence, France and Germany declined to call the killings genocide. Pakistan, currently a member of the U.N. Security Council, warned of the danger in terminating engagement with Sudan's government. China, the leading foreign investor in Sudan's burgeoning oil fields, said it might veto a tough Security Council resolution.

Mr. Powell cannot be blamed for the cynicism of other powers, but he does face a choice about how to respond to it. So far he has attempted to lead from within the pack: The United States has drafted U.N. resolutions but has been careful to word these gently in an effort to bring allies along; it has supported negotiations between Sudan's government and Darfur's two rebel groups, but it has mostly left the mediation to the Nigerian government. The result is a draft U.N. resolution that is likely to be too weak to affect Sudan's behavior and negotiations that have wasted time on misguided proposals, for example, that the rebels agree to be confined within cantons while ceding control of nearly all territory to the government.

The Bush administration should set its sights higher. As Mr. Powell told the Senate on Thursday, the goal must be to get a large, neutral civilian-protection force into Darfur, so that the continuing murders and rapes can at last be ended. This will not happen unless Sudan's government invites the force in; but the invitation must be squeezed out of the regime by means of U.N. sanctions. Of course, China and its allies may attempt to block this path. But do these countries really want to cast themselves as abettors of genocide? Mr. Powell and President Bush must force them to answer that question.