Matthew Iglesias has an interesting piece in the American Prospect about whether the circumstances in Darfur constitute genocide and why this matters:
As everyone knows by now, terrible atrocities have been and are continuing to be committed against the civilian population of Darfur in Sudan. According to many observers, these atrocities amount to the crime of genocide. In terms of international law, they may well be correct. But, though I fear I may get thrown out of polite society for saying so, I think that choice of terms should be resisted. The legal definition is a bit broad, and it's best to leave it up to the lawyers at the State Department and the United Nations to argue over whether it fits the case at hand. What comes to mind when non-lawyers hear the word "genocide," however, is something akin to the events of the Holocaust, where a regime pursues the destruction of an ethnic group as an end in and of itself. Without denying that monstrous things are being done in Darfur, I don't think that genocide -- in this sense -- is what's happening.
His point is that the killings in Darfur arose as a tactic in a war, not simply as a desire to exterminate a particular group. And this matters because once we recognize that a war is taking place, we need to address a number of hard questions before considering any intervention. Reasonable people might still advocate intervention. But they should have good answers for all the questions that Iglesias poses in order to make their case.