As much as this idea is heresy at the State Department, perhaps allowing Iraq to divide into three states—Sunni in the west, Shiite east, and Kurd north—would be a more “natural” division along ethnic lines.
Fearing just such a three-way split as a “power vacuum“, Bush (41) aborted the Gulf War in 1991. Big mistake, as we now know. The younger Bush (43) finally got rid of Saddam Hussein, but did nothing for the political, ethnic and religious divisions. Obama simply withdrew, and nature (as practiced in the Middle East) is following its course.