Explore 22 FRONTLINE documentaries that chronicle the U.S.-led March 2003 invasion of Iraq, its long and bloody aftermath and the enduring impact on ordinary Iraqis and U.S. soldiers.
Two controversial Iraq War-era militia leaders announced a political alliance between their blocs, raising questions about the future of American involvement in the country.
Shia militias stepped in to fight ISIS when Iraq's army collapsed, but the involvement of some groups accused of sectarian violence has alienated much of the nation's Sunni population.