With the spread of ethnic and sectarian violence in Iraq — brought to new levels of terror by the rise of the Islamic State — Iran's image as an island of stability in a conflict-ridden Middle East may be short-lived. Its government — already struggling to manage a decrepit economy and tricky nuclear negotiations with the international community — now faces serious questions over its Iraq policy and a "winner-takes-all" mind-set that could eventually threaten Iran's own national security.
Iran's policy toward its western neighbor appears to have two main goals: preservation of influence there, and prevention of any spillover of Iraq's ethnic conflicts into its own multi-ethnic and multi-confessional society.
But as Iran steps up military support for the Iraqi government, Iranian officials fear, quite reasonably, that intervention could suck the country into an open-ended sectarian civil war.