The Iraq War was an armed conflict in Iraq. It is usually dated to begin with the invasion of Ba’athist Iraq starting on 20 March 2003 by an invasion force led by the United States, although clashes between the Iraqi military and U.S./U.K. air forces had been ongoing since December 1998. It was followed by a longer phase of fighting, in which an insurgency emerged to oppose the occupying forces and the newly formed Iraqi government. The U.S. completed its withdrawal of military personnel in December 2011. However, the Iraqi insurgency continues and caused thousands of fatalities in 2012.
Prior to the war, the governments of the United States and the United Kingdom claimed that Iraq’s alleged possession of weapons of mass destruction (WMD) posed a threat to their security and that of their coalition/regional allies. In 2002, the United Nations Security Council passed Resolution 1441 which called for Iraq to completely cooperate with UN weapon inspectors to verify that Iraq was not in possession of WMD and cruise missiles. Prior to the attack, the United Nations Monitoring, Verification and Inspection Commission (UNMOVIC) found no evidence of WMD, but could not yet verify the accuracy of Iraq’s declarations regarding what weapons it possessed. After investigation following the invasion, the U.S.‑led Iraq Survey Group concluded that Iraq had ended its nuclear, chemical and biological programs in 1991 and had no active programs at the time of the invasion, but that they intended to resume production if the Iraq sanctions were lifted. Although some degraded remnants of misplaced or abandoned chemical weapons from before 1991 were found, they were not the weapons which had been one of the main arguments for the invasion.
Some U.S. officials also accused Iraqi President Saddam Hussein of harboring and supporting al-Qaeda, but no evidence of a meaningful connection was ever found. Other proclaimed reasons for the invasion included Iraq’s financial support for the families of Palestinian suicide bombers, Iraqi government human rights abuses, and an effort to spread democracy to the country.
On 16 March 2003, the U.S. government advised the U.N. inspectors to exit Iraq and the following day Bush issued a 48-hour ultimatum demanding Saddam and his sons to go into exile. On 20 March the American-led coalition conducted a surprise military invasion of Iraq without declaring war. The invasion led to an occupation and the eventual capture of Saddam Hussein, who was later tried in an Iraqi court of law and executed by the new Iraqi government. Free elections were held in 2005 resulting of the formation of a Shi’a led government under Prime Minister Nouri Al-Maliki. Violence against coalition forces and among varioussectarian groups soon led to the Iraqi insurgency, strife between many Sunni and Shia Iraqi groups, and the emergence of a new faction of Al-Qaeda in Iraq.
In June 2008, U.S. Department of Defense officials claimed security and economic indicators began to show signs of improvement in what they hailed as significant and fragile gains. Iraq was fifth on the 2008 Failed States Index, and sixth on the 2009 list. As public opinion favoring troop withdrawals increased and as Iraqi forces began to take responsibility for security, member nations of the Coalition withdrew their forces. In late 2008, the U.S. and Iraqi governments approved a Status of Forces Agreementeffective through 1 January 2012. The Iraqi Parliament also ratified a Strategic Framework Agreement with the U.S., aimed at ensuring cooperation in constitutional rights, threat deterrence, education, energy development, and other areas.
In late February 2009, newly elected U.S. President Barack Obama announced an 18-month withdrawal window for combat forces, with approximately 50,000 troops remaining in the country “to advise and train Iraqi security forces and to provide intelligence and surveillance”. UK forces ended combat operations on 30 April 2009. Iraqi Prime Minister Nouri al‑Maliki said he supported the accelerated pullout of U.S. forces. In a speech at the Oval Office on 31 August 2010 Obama declared “the American combat mission in Iraq has ended. Operation Iraqi Freedom is over, and the Iraqi people now have lead responsibility for the security of their country.” Beginning 1 September 2010, the American operational name for its involvement in Iraq changed from “Operation Iraqi Freedom” to “Operation New Dawn”. The remaining 50,000 U.S. troops were designated as “advise and assist brigades” assigned to non-combat operations while retaining the ability to revert to combat operations as necessary. Two combat aviation brigades also remain in Iraq. In September 2010, the Associated Press issued an internal memo reminding its reporters that “combat in Iraq is not over”, and “U.S. troops remain involved in combat operations alongside Iraqi forces, although U.S. officials say the American combat mission has formally ended”.
On 21 October 2011, President Obama announced that all U.S. troops and trainers would leave Iraq by the end of the year, bringing the U.S. mission in Iraq to an end. On 15 December 2011, U.S. Defense Secretary Leon Panetta officially declared the Iraq War over, at a flag lowering ceremony in Baghdad. The last U.S. troops left Iraqi territory on 18 December 2011 at 4:27 UTC.