Civil War in Iraq: effect on Iran

Charles Krauthammer says of course it's a civil war...Duh!!, but several others like Ian Bremmer and Bill Roggio have contributed, IMHO, a more sober and less sensationalistic analysis of what Civil War really means.

I notice a conventional wisdom coalescing about the idea that civil war would somehow benefit Iran. I wonder if we should accept this opinion. Clear evidence exists that Iran has agents fomenting unrest via the Badr and Sadr militias, but is Iran certain that they could confine any type of widespread sectarian violence to within the current borders of Iraq? Clearly, a power vacuum would lead to ingress of multitudes of proxy militias if the issue is Sunni vs. Shia, and unfortunately the Shia are outnumbered if you look at the total numbers of Muslims all over the world.

Consider the Iranian Sunni Arabs who are quite numerous around the oil fields and ports of southern Iran. They are not likely to remain idle in a regional sectarian conflict and could conceivably put a hurt on Iranian oil exports or otherwise provide aid to the minority Sunnis Arabs in Iraq.

I might even venture the outrageous observation that fomenting a civil war in Iraq might even relieve some of our own problems in the region, by giving Islamists somebody else to blow up, and by providing the Iranian mullarchy another use for their resources: IRBM's and nuclear warheads might not nearly be as useful against IED's and guerilla warriors. Iraq-Iran War II.