U.S troops leave Iraq: How a 23 year military presence unfolded | Explained

U.S. forces are set to leave their last bases in Iraq, bringing an end to a 23-year military presence that began with the 2003 invasion that removed Saddam Hussein from power. From the years of insurgency and the 2011 withdrawal to the rise of Islamic State and the return of U.S. troops in 2014, here is how America’s military role in Iraq unfolded and why concerns over Iraq’s security remain.