I agree that a Civil War should not have any interference. During the Civil War in America, the Union (who was favored) was worried that British or French troops would ally with the Confederacy. If that HAD happened, the entire outcome of the globe would be different.
Unfortunetely, with all the "progress" in Iraq, it's just going to become more screwed up than it is now, which is already more screwed up then it was before the "liberation". If one tribe were to conquer the other (Sunni or Shiite), the "government" would sort itself out. However, that would result in genocide.
And a civil war has been going on in Iraq for a few years now; only after the bombing of the holiest mosque did it get any media play.
Peace sells... but who's buying.