Of course Iraq will fall apart.
It was destined to fall apart.
Inimical religions and races living in an artificial nation created by a former external imperial power. It was created by force, and always held together by force.
The force was removed.
And now it must fall to pieces, or be welded back together by force.
There is a low grade civil war going on, which is only made low grade by the fact only one side is fighting it.
The only way to pacify the place is the way it always has been pacified, by the Turks, then by Saddam: civil war that thins out the males of the losing side enough that they cannot effectively continue the fight.
If course the US does not want to do this. So it's just a long, slow burn, waiting for the war to come.
Good points, but I have some optimism that things will not turn out that way.
"Inimical religions and races living in an artificial nation .... It was created by force, and always held together by force."
That describes most states on planet earth.
Iraq will vote on the Constitution, vote yes, and the issue will be settled.