The political battle raging in Baghdad over the appointment of new Cabinet ministers is merely a subset of an overarching regional competition. Late last week, U.S. Secretary of State John Kerry's surprise visit to Baghdad was meant to show Washington's continued involvement in building an Iraqi government that will focus sufficient attention on the fight against the Islamic State while maintaining some distance from Tehran. Even so, U.S. and Iraqi leaders are coming to terms with the United States' noticeably diminished presence in Baghdad as competing priorities pull Washington in other directions. That leaves Turkey as the primary Sunni power to counterbalance Iranian influence in Iraq....