The demonstrators had extraordinary moral credibility.

Last week in Kigali, Rwanda, survivors of the 1994 Rwanda genocide called on the United Nations and world leaders to act to end the continuing genocide in Sudan's western Darfur region.

"We survivors stand with the victims in Darfur," Rwandan Freddy Umutanguha told The Irish Independent. "We know what it is like to lose our mothers, fathers, brothers, sisters, sons and daughters."

In April 1994, Hutu-led mobs and militias began slaughtering 800,000 mothers, fathers, sons and daughters -- mostly Tutsi tribespeople, though Rwandan Hutus who opposed the killers were also slain. The murder campaign continued for three months.

Since February 2003, at least 250,000 people have been killed in Darfur. Another 2.5 million have been displaced.

In February 2004, reflecting on Rwanda's genocide, U.N. Secretary General Kofi Annan said: "There can be no more binding obligation for the international community than the prevention of genocide. ... The events in Rwanda ... were especially shameful. The international community clearly had the capacity to prevent those events, but failed to summon the will. ... We must ensure that we never again fail to summon the will." Lack of political will and lack of credible military power contributed to the Rwandan disaster.

A U.N. peacekeeping force deployed to Rwanda in 1993 to monitor a ceasefire agreement between the Rwandan government and a Tutsi rebel group, the Rwandan Patriotic Front (RPF). I am not convinced that small and lightly armed force could have done much -- there were too few of them, and the genocidal attacks quickly spread throughout Rwanda. However, Canadian Gen. Romeo Dallaire, the U.N. force commander, now believes early, decisive action against the Hutu extremists who led the genocide would have thwarted their plans. Dallaire's U.N. troops would have been intervening in a Rwandan civil war, but in retrospect he thinks that was the least-terrible choice.

The peacekeepers did not intervene, however. Belgium withdrew its contingent when 10 soldiers were killed. U.N. leaders dithered for weeks before voting to reinforce the mission, sending too little, too late.

The mounting death toll in Darfur tests Annan's stirring words. But when it comes to ending genocide, words require swords. Fine words cannot protect the vulnerable from dedicated killers -- that job demands soldiers.

Annan knows this. Annan, with the support of the United States and Great Britain, wants to reinforce the hapless, ineffective African Union peacekeeping force now in Darfur. In August, the Security Council approved a U.N.-led force. But the resolution "invites" the consent of the Sudanese government in Khartoum to approve deploying U.N. troops. Continued...