The question is, Is there a will?
Lets be frank, here. Iraq doesn't want to be one unhappy family.
Kurds do not want, and have never wanted to be part of Iraq when britain carved it into the sand (arbitrarily). The Sunni Arabs only wanted Iraq because it was a big empire to them, where there 20% got to rule 100% of the country (and take a disproproportiate amount of wealth), now that they aren't in charge..they don't want to be in the same country as the Shia anymore.
The Shia (now) want an Iraq because they have a shot at controlling the rest of it and all the oil wealth at the expense of the other groups who live there.
I know this may be hard to believe, but Iraq is the frontline between Arab, Kurd and Persian land claims, its one of those fake countries carved into the map by European goals at the end of WWI.
@ Darkbeaver:
Yes, Israeli and Syrian intervention have turned lebanon into a hellhole as they fight their proxy wars.
You think Iran and Turkey won't fight their own proxy wars? A militantly Islamic and a militantly Secular nation with a their own interests to secure?
I know its a stretch, but people other than America and Israel are able to have their own goals independant of those two nations, and will commit their own meddlesome acts in their neighbours affairs to pursue those goals.
Not everything in the world is the fault of, or even remotely related to, America and Israel.
Which is the point, Iraq has its own problems whether or not America is there and will continue to have its own problems whether or not America stays there.