Monday the Iraqi military launched its largest operation to date against the self-declared Islamic State (IS), also called ISIS, to retake control of the city of Tikrit. Alongside the Iraqi military the coalition fighting IS in Tikrit includes Kurdish and Sunni tribal forces, but it leans heavily on Iranian backed Shia militias and reportedly includes a contingent from Iran's revolutionary guard. The urgent question now as the battle against IS intensifies is whether any US policy to defeat IS in Iraq can achieve its aim without ceding the country as a base for Iranian expansionism. Critics who regard President Obama's regional policy as aiming for a grand d