Claim: Iraq was invaded by the United States.

The Iraq War '' ` The conflict is also known as the War in Iraq , the Occupation of Iraq , the Second Gulf War , and Gulf War II . The period of the war lasting from 2003 to 2010 was referred to as Operation Iraqi Freedom by the United States military . was a protracted armed conflict that began in 2003 with the invasion of Iraq by a United States-led coalition that toppled the government of Saddam Hussein . The conflict continued for much of the next decade as an insurgency emerged to oppose the occupying forces and the post-invasion Iraqi government . An estimated 151,000 to 600,000 or more Iraqis were killed in the first 3 -- 4 years of conflict . It became re-involved in 2014 at the head of a new coalition ; the insurgency and many dimensions of the civil armed conflict continue .   The invasion began on 20 March 2003 , with the U.S. , joined by the United Kingdom and several coalition allies , launching a `` shock and awe '' bombing campaign . Iraqi forces were quickly overwhelmed as U.S. forces swept through the country . The invasion led to the collapse of the Ba'athist government ; President Hussein was captured during Operation Red Dawn in December of that same year and executed by a military court three years later . However , the power vacuum following Saddam 's demise and the mismanagement of the occupation led to widespread sectarian violence between Shias and Sunnis , as well as a lengthy insurgency against U.S. and coalition forces . The United States responded with a troop surge in 2007 . The winding down of U.S. involvement in Iraq accelerated under President Barack Obama . The U.S. formally withdrew all combat troops from Iraq by December 2011 .   The Bush administration based its rationale for the war principally on the assertion that Iraq possessed weapons of mass destruction -LRB- WMDs -RRB- and that the Iraqi government posed an immediate threat to the United States and its coalition allies . Select U.S. officials accused Saddam of harboring and supporting al-Qaeda , while others cited the desire to end a repressive dictatorship and bring democracy to the people of Iraq . After the invasion , no substantial evidence was found to verify the initial claims about WMDs . The rationale and misrepresentation of pre-war intelligence faced heavy criticism within the U.S. and internationally .   In the aftermath of the invasion , Iraq held multi-party elections in 2005 . Nouri al-Maliki became Prime Minister in 2006 and remained in office until 2014 . The al-Maliki government enacted policies that were widely seen as having the effect of alienating the country 's Sunni minority and worsening sectarian tensions . In the summer of 2014 , the Islamic State of Iraq and the Levant -LRB- ISIL -RRB- launched a military offensive in Northern Iraq and declared a worldwide Islamic caliphate , eliciting another military response from the United States and its allies . The Iraq War caused hundreds of thousands of civilian , and thousands of military casualties -LRB- see estimates below -RRB- . The majority of casualties occurred as a result of the insurgency and civil conflicts between 2004 and 2007 .