After all, the whole point of the United Nations system was to provide a way for the great powers to collaborate with one another -- when they agree. On Darfur, four of the five permanent veto-wielding powers did agree, and the fifth, China, merely abstained. So this should signal that they mean business. If not, the UN Security Council is wasting their and, more importantly, all of our time passing resolutions that they don't care about.

For they should care about Darfur. The case for external intervention to prevent further bloodshed, further massacres is as strong as it could possibly be. The massacres have been happening. Other means have been tried to persuade the Sudanese government to stop them, including the African Union force. If humanitarian intervention is ever again to be contemplated, or even taken seriously, then it needs to be done in Darfur, even against the wishes of the sovereign government of Sudan.

China is a problem. But China is also an opportunity: the best next effort would be to persuade the Chinese to lean on their new commercial partners in Sudan to let the UN force in. China, like Russia, does not like the idea of intervention against the wishes of sovereign governments. But China is also showing signs of wanting to take on the responsibilities of being a great power, or at least the recognition that that is what it is.

Here is China's chance. If it doesn't use it, the other UN Security Council members should go ahead with intervention. China is unlikely to block it. Like the Arab League, it may not want to stand up explicitly against Sudan. But it would surely stand aside if the other great powers were truly determined. And they should be. Because if they are not over Darfur, then we can all kiss goodbye to the idea of humanitarian interventions.