In a special developing report, FRONTLINE examines the unfolding chaos in Iraq and how the U.S. is being pulled back into the conflict. Drawing on interviews with policymakers and military leaders, the investigative team behind The Lost Year in Iraq, The Torture Question, Endgame and Bush’s War traces the U.S. role from the 2003 invasion to the current violence — exploring how Iraq itself is coming undone, how we got here, what went wrong and what happens next.