I do find it odd how many people now say that if only pesky Iran would get out of the way then Iraq would be fine. As if somehow Iran is the true problem with Iraq, and that it's not that the Iraqis just hate each other for their ethnic differences. Kind of like how when the Sunni insurgents were the problem, everyone said that they're just Saddam loyalists that will be crushed as soon as Saddam is gone.
Why is it that it's always some other party's fault that Iraq is a mess, and not ours, or the Iraqis? It's either Iran, Syria, Saddam, whatever. The truth is that it's both our fault and the Iraqis fault. These sectarian tensions already existed - Sunnis hated Shi'ites, and that's how its always been there. Bush and the majority of the U.S. government was so ignorant of other cultures that they didn't even know what the differences are between Shi'a and Sunni Muslims. We invaded and took out the system that was in place to keep order. Now, they're cutting each other's throats. Iran has nothing to do with it. Syria has nothing to do with it. Saddam has nothing to do with it. This is a religious war between two rival sects, allowed to take place due to our invasion.
Don't blame other nations for the situation in Iraq. We can only blame ourselves and the Iraqis. I have yet to see any evidence that other nations are behind the violence in Iraq.