Stormin' Norman would have ended up in the same shit.

Iraq was carved out of the Ottoman Empire by the winners in WW1, along with other artificial 'nations'. Lines were drawn on the map by French and British politicians, and natural relationships destroyed.
The only way to keep the three elements together is with a rigid dicatorship, but we can't put humpty back together- we kicked out Saddam, destroyed his army and police, and wrecked the infrastructure.
If things had been left alone to evolve, in time the Sunnis, Shia and Kurds, already becoming resigned to living and working together under Saddam, might have eventually developed a vital country. It was beginning to look like that could have happened in time.

Democracy has to evolve, not be imposed at gun point on cultures used to different ways.