Remember when Turkey wouldn't let the U.S. go through its country to invade Iraq? Now the Turkish military is talking about moving into northern Iraq on its own. It seems that Kurdish separatists within Turkey are hiding in northern Iraq and Turkey wants to go in and get them.
For now, the Turkish military is holding itself back and waiting for civilian leaders to make the call. So let's imagine that the U.S. is pulled out of Iraq altogether, which is the best. The new Iraq now has to worry not only about Iran menacing them, but Turkey too. Not to mention Kurd separatism erupting in northern Iraq at the same time. Let's not forget the oil there.
If Iraq blows up, then Iran and Turkey will have good reasons to march in. I think what the Iraqis will find is that they had better hang together, or they will surely hang separately.