Rwanda's civil war vs. Iraq's civil war

I saw Hotel Rwanda recently. A theme of the movie, one I agree with, is moral outrage with the West for failure to intervene in the slaughter, save to rescue white foreign nationals.

I opposed and still oppose the Iraq war. Its liberal critics warned time and again that our unnecessary provocation could start a civil war. One may be brewing.

In my mind, in an attempt to be honest with myself, I'm trying to come up with a unified theory about when exactly military intervention is a good thing. If we were to pull out of Iraq, would there be a need for the kind of intervention force the Rwandans pined for and never came? On the other hand, could a Western occupation of Rwanda in have been as futile as the American and British one appears to be in Iraq-- could it have merely introduced new provocations?

But then as I type, I remember how the folks were ultimately saved. The hero of the movie has a conversation with a general who was either secretly complicit or officially disinterested in the slaughter. The hero goads the general into action by stressing the effect of the generals' action on his international reputation. The general's troops then stop the slaughter at the hotel. Maybe Western soldiers couldn't have done what an African general could, what a respected African civilian could demand of an African general.

More on this later if I come to any conclusions.