This report provides an overview of Iraq's political transition from the dictatorship of Saddam Hussein to a plural polity that encompasses varying sects and ideological and political factions. This report also addresses ongoing governmental instabilities and their causes, as well as U.S. concerns about possible Iranian influence in Iraq as U.S. forces depart the country.

With a conventional military and weapons of mass destruction (WMD) threat from Saddam Hussein's regime removed, Iran seeks to ensure that Iraq can never again become a threat to Iran, either with or without U.S. forces present in Iraq. By supporting armed Shiite factions, Iran's influence in Iraq has at times hindered U.S. efforts to stabilize Iraq, and has heightened the U.S. threat perception of Iran generally. However, Iran faces difficult choices in Iraq now that its protege Shiite factions, formerly united, are competing and often fighting each other.