Personally, and I am sure I will get flamed for this, this is why Iraq has been so much more difficult than anyone thought, and why we still might have to be there a long time.
It’s just like yugoslavia.. three distinct cultures that don’t want to live together. The only successful was to make them live together is with the force of a brutal tyrant.
Split it up.
If only it were that simple in Yugoslavia, but it wasn't. Neither Bosnia nor Kosovo had ever been "countries". Croatia had a history of genocide against the many Serbs living their (who had been there for centuries).
It wasn't as easy as drawing lines with a pen and saying "poof, you are independent". Virtually all of the animosity between people in the Balkans can easily be attributed to foreign meddling and internationals "redrawing borders" over the centuries.
Fact is that if we really wanted "peace" and not just a predetermined outcome, we should have never got involved there at all. Instead, we are still in Bosnia, propping up some phony country ten years later, and we are still in Kosovo and will be for the foreseeable future, do the same. What a waste of time resources, and manpower!
I take it then that you are fine with the idea of the Confederacy rising again and the Mexicans reconquering Aztlan?
well, more than 3 — the Kurds (Aryanic/Indo-European people), the Arab Sunnis, the Arab Shias and then also the Christian Chaldeans/Assyrians, then the tiny communities of Manecheans and Sabeans who are Semitic while Yazidis are Irani peoples (like the Kurds)