Sunni-Shiite is so 2007. Visiting the Kurdish region of Iraq on Wednesday, Secretary of Defense Robert Gates cited Kurd-Arab tensions as the greatest threat to Iraqi national security. General Ray Odierno, the top U.S. commander in Iraq, seconded Gates’ diagnosis, calling the conflict in northern Iraq the “no. 1 driver of instability." In a meeting with Kurdish President Massoud Barzani, Gates apparently stressed that he supports U.N. recommendations on how to resolve disputes between Iraqi Arabs and Kurds.