The Iraq situation, briefly
From your post:
"(Iraq) is made up of Sunnis, Shias and Kurds, each of which group distrusts and dislikes the others."
That's a lot of simple minded bull$hit.
Here are the true facts:
1. Sunni Kurds, in the North have organized themselves into an independent nation. They have a democratic secular government and a strong militia. They also have less than half the oil. They want to maintain their independence from all Arabs, Sunni and Shia.
2. Shia Arabs, in the South have more than half of the population and the bulk of the oil. They are now following the Kurds' model and establishing an independent nation, most likely a theocracy, allied with Iran.
3. Sunni Arabs in the middle want to resume exploiting the Sunni Kurds and Arab Shias, who have all of Iraq's oil, in the North and South. Sunni Arabs are Saddam Hussein's people. They have been exploiting the other two groups for 80 years and especially brutally during Saddam Hussein's rule of 30 years. They see their control slipping away and the have mounted the insurgency in order to create chaos, which might enable them to seize power again.
The United States is irrelevant.