As a test of the world's "responsibility to protect," Darfur has been a miserable failure.

For four years the people of Darfur have been murdered and raped by the militias backed by the government of Sudan, and the world has been unwilling to stop the violence. Last week, the United Nations, having at last obtained the consent of Sudan, passed a resolution to send in a large, African-led peacekeeping force. It is good news that a meaningful intervention is on its way; many lives remain to be saved. But the UN did not live up to the responsibility proposed by Canada and others in 2001 and accepted by the world body two years ago. The UN resolution, co-sponsored by Britain and France, has some teeth and some gaps. Assuming that the world antes up enough soldiers (mostly from Africa and the Middle East, since Canada, the United States and Europe are tied up in Afghanistan and Iraq), the force is to have nearly 20,000 soldiers and more than 6,000 police. The African Union contingent of 7,000 already in Darfur will be folded into this joint UN-AU mission, to be up and running by the end of the year.

This should not be an impotent group of soldiers on perpetual standby, as was the case with UN peacekeepers in Rwanda under the command of Canadian general Romeo Dallaire. Resolution 1769 authorizes the peacekeepers to "take the necessary action" to protect their own personnel and the freedom of movement of aid workers, to prevent a peace agreement from being disrupted, and to protect civilians. It is unfortunate, however, that the peacekeepers have no power to disarm the janjaweed ("evil men on horseback") militia. Amnesty International has raised concerns that the force can only monitor arms in Darfur, and that the Islamist government of Sudan will try to obstruct the UN-AU force.

Sovereignty is not absolute. The responsibility to protect is based on the idea that, in extreme cases, an international duty to save civilians trumps the sovereign rights of states. Darfur is an extreme case. At least 200,000 civilians have died and more than two million (out of a population of six million) have been displaced. Whether there was genocidal intent or not is irrelevant. "There is a collective international responsibility to protect," a report commissioned by former UN secretary-general Kofi Annan in 2004 said, "exercisable by the Security Council authorizing military intervention as a last resort in the event of genocide and other large-scale killing, ethnic cleansing or serious violations of international humanitarian law which sovereign governments have proved powerless or unwilling to prevent."

But the collective responsibility became tangled up in the machinery of the United Nations, in part because China, a Security Council member and a major importer of Sudan's oil, opposed the intervention. The worst human suffering in recent times has sprung from civil war and ethnic conflict rather than battles between nations, and the world has had no ready response to it.