Ethnic groups exist together all over the world in sometimes "uneasy" but relative peace none-the-less. It's an economic issue with them as well, and I'm defining "economic" in its broadest sense. Anything from a crust of bread up to a private jet is an economic commodity. All living things must fulfill their basic economic needs before any other consideration. We keep redefining "basic" though.
When a society has nothing there isn't a lot of internal struggle beyond that of survival. No one should believe that the survival of the Iraqi ethnicity is in question. The Iraqis just don't yet have "enough" distributed economic equity to form inter-ethnic or religeous co-existance.
******, for example, rose from the inequity the German people felt after the defeat of WWI. Not just because he could belt out a speech. The society bought into it.
The similiarities between Shia and Sunni far overwhelm their differences but yet the emotional differences are magnified to the absurd by leaders on both sides to whip the populace into acting violently. They ignore the substantive similiarities, and even their own "higher principals." (think not only about a ******, but about silly Demos and Repubs on gay marriage or abortion)
Saddam didn't rule by force alone, he didn't posess enough secret police. The populace allowed themselves to be so governed. All society "allows" itself to be governed. "By the consent of the people."
People ALWAYS act in their own self interest, whether it's an altruistic, Mother Theresa quest for fulfillment, or an all consuming drive for power. Peace and stability insue not when we give up our own self interest, but when our cummulative self interests align. That's not a bad thing. It may not sound "noble" but nobody ever continued to do anything very good, for very long that made them feel very bad for very long (or that killed them.
) That's where resentments come from, fester and grow, then potentially explode.
Saddam didn't "force" Shia and Sunni to co-exist, they did it because it was economically beneficial to do so given the alternatives. Economic control was understood, as well as who had it, and what was needed to do to get some of it. Now there is a vacuum.
The "coalition" forces disrupt the equation. Any "side" favored has a distinct appearance of advantage. We can debate the actual advantage, but if you're Joe Iraqi, and you're not of the opinion that the coalition aided government will support you...you won't share in the economic benefit of the society...you're not going to accept it. Your percieved risk is too great, greater than just "going along."
Get rid of the percieved "unfair" imbalance of the coalition, and Joe Iraqi will decide that he and his neighbor are in it together once again. He may not like the outcome, but he'll stop killing people. He'll then pull in a greater number to his cause, "tension" may not go away entirely, but Joe will say, "yeah, but "he's a good Sunni.....live and let live" once again. The fringes will recede, and the rhetoric will fail to draw as many....
That's how it works here in the melting pot of the west, we don't all agree, and we don't all like each other after all....
The process will repeat, as it always has....since history began. It's why we don't seem to apply what we learn individually to societies as a whole, we can't give up our instinctual need to survive as a society. "None of us is as dumb as ALL of us."
The REAL question is: before the nuclear age, we COULD sit back and ignore the struggles of others in isolation if we chose, can we now? Our self interest of survival, of our "basic" needs, is now potentially affected.