Like any geopolitical crisis, Darfur is complex. But at the risk of simplifying to the point of incoherence, there are really only two options on the table:
1) Allow the African Union to take the military lead and provide them with money and logistical support. As far as I can tell, this is just wishful thinking. The AU has never been effective at much of anything, it's riven by internal politics, and all the money and materiel in the world won't change that in the short term. There may be pressure points here that I'm missing, but relying on the AU strikes me as little more than an excuse to sound virtuous while doing nothing.
2) Send in western troops. But whose? Both America and Britian are mostly tied down in Iraq and Afghanistan. NATO's deployable troops are largely committed to Afghanistan. France, which has both bases and (a small number of) troops in central Africa, has shown little interest in using them.
This is not a trivial problem. "Troops" and "deployable troops" are not the same thing, and very few countries aside from the U.S. and (to a smaller extent) Britain have troops in any significant numbers that they can deploy overseas. This year-old article by David Englin outlines the military situation, and although military intervention is indeed doable, my guess is that it would take a serious commitment to local air superiority plus a minimum of three or four divisions of combat troops with rules of engagement sufficiently robust to allow them to stop the Janjaweed slaughter. Make no mistake: this would basically be a declaration of war against Sudan.
I've been a big booster of sending in Western troops. But Drum has a point, they aren't exactly in common supply right now. I think we probably could rustle up enough if there really was a will to do it. But I'm skeptical that the motivation will ever come to override the inertia that dominates international affairs.
Drum says he might be willing to more vocally support a Darfur operation if he saw a clear plan that shows how, with whom, and to what end we will intervene. Perhaps someone should get on that...?