Another One?

Yet another "ethnic cleansing" occurring in the world, this time in Iraq. The US army recently found material that a Shiite militia is slowly and methodically removing Sunni families from Wabash. After seeing more and more news coming out of Iraq of incidents like this, I'm starting to wonder if the presence of the "coalition of the willing" is really helping the people of Iraq, or if matters are only getting worse. To the best of my knowledge, the problem's existed since the collapse of the Ottoman empire, and the drawing of maps to natural lines, rather than ethnic lines, in essence, smooshing people together that hate each other. Is there a solution to this problem, or is US isolationism the only cure?