Iraq War

Iraq War
Part of the Iraqi conflict and the War on Terror
Iraq War montage.png
Clockwise from top: U.S. troops at Uday and Qusay Hussein's hideout; insurgents in northern Iraq; an Iraqi insurgent firing a MANPADS; the toppling of the Saddam Hussein statue in Firdos Square
Date
  • 20 March 2003 – 18 December 2011 (2003-03-20 – 2011-12-18)
    (8 years, 8 months and 29 days)
Location
Result
Belligerents
Invasion phase (2003)
 United States
 United Kingdom
 Australia
 Poland
Peshmerga
Supported by:
 Italy[1]
 Netherlands[2]
Invasion phase (2003)
 Iraq

Post-invasion
(2003–11)
Iraq
 United States
 United Kingdom

MNF–I
(2003–09)

Supported by:
Iran Iran[3][4]
 Iraqi Kurdistan

Post-invasion (2003–11)
Ba'ath loyalists


Sunni insurgents


Shia insurgents

Supported by:
 Iran

Commanders and leaders
Ayad Allawi
Ibrahim al-Jaafari
Nouri al-Maliki
Ricardo Sanchez
George W. Casey, Jr.
David Petraeus
Raymond T. Odierno
Lloyd Austin
George W. Bush
Barack Obama
Tommy Franks
Donald Rumsfeld
Robert Gates
Tony Blair
Gordon Brown
David Cameron
John Howard
Kevin Rudd
Silvio Berlusconi
Romano Prodi
Sheikh Jaber (Natural Causes)
Sheikh Sabah
José María Aznar
Anders Fogh Rasmussen
Aleksander Kwaśniewski
Lech Kaczyński

Saddam Hussein (POW) Skull and Crossbones.svg
Izzat Ibrahim ad-Douri 
Iraq Qusay Hussein 
Iraq Uday Hussein 
Iraq Abid Hamid Mahmud (POW) Skull and Crossbones.svg
Iraq Ali Hassan al-Majid (POW) Skull and Crossbones.svg
Iraq Barzan Ibrahim (POW) Skull and Crossbones.svg
Iraq Taha Yasin Ramadan (POW) Skull and Crossbones.svg
Iraq Tariq Aziz (POW)
Iraq Mohammed Younis al-Ahmed


Sunni insurgency
Abu Musab al-Zarqawi 
Abu Ayyub al-Masri 
Abu Omar al-Baghdadi 
Abu Bakr al-Baghdadi 
Islamic Army of Iraq (emblem).png Ishmael Jubouri
Abu Abdullah al-Shafi'i (POW)


Shia insurgency
Muqtada al-Sadr
Shiism arabic blue.svg Abu Deraa
Qais al-Khazali
Akram al-Kaabi
Iran Qasem Soleimani [14]
Strength

Invasion forces (2003)
309,000
 United States: 192,000[15]
 United Kingdom: 45,000
 Australia: 2,000
 Poland: 194
Kurdistan Region Peshmerga: 70,000

Coalition forces (2004–09)
176,000 at peak
United States Forces – Iraq (2010–11)
112,000 at activation
Security contractors 6,000–7,000 (estimate)[16]
Iraqi security forces
805,269 (military and paramilitary: 578,269,[17] police: 227,000)
Awakening militias
≈103,000 (2008)[18]
Iraqi Kurdistan
≈400,000 (Kurdish Border Guard: 30,000,[19] Peshmerga 375,000)

Coat of arms of Iraq (1991–2004).svg Iraqi Armed Forces: 375,000 (disbanded in 2003)
Iraqi Republican Guard Symbol.svg Special Iraqi Republican Guard: 12,000
Iraqi Republican Guard Symbol.svg Iraqi Republican Guard: 70,000–75,000
Fedayeen Saddam SSI.svg Fedayeen Saddam: 30,000


Sunni Insurgents
≈70,000 (2007)[20]
Al-Qaeda
≈1,300 (2006)[21]

Islamic State of Iraq
≈1,000 (2008)
Army of the Men of the Naqshbandi Order
≈500–1,000 (2007)
Casualties and losses

Iraqi security forces (post-Saddam)
Killed: 17,690[22]
Wounded: 40,000+[23]
Coalition forces
Killed: 4,825 (4,507 U.S.,[24] 179 U.K.,[25] 139 other)[26]
Missing/captured (U.S.): 17 (9 died in captivity, 8 rescued)[27]
Wounded: 32,776+ (32,292 U.S.,[28] 315 U.K., 210+ other[29])[30][31][32][33] Injured/diseases/other medical*: 51,139 (47,541 U.S.,[34] 3,598 UK)[30][32][33]
Contractors
Killed: 1,554[35][36]
Wounded & injured: 43,880[35][36]
Awakening Councils
Killed: 1,002+[37]
Wounded: 500+ (2007),[38] 828 (2008)[39]

Total dead: 25,069
Total wounded: 117,961
Iraqi combatant dead (invasion period): 5,388–10,800[40][41][42]
Insurgents (post-Saddam)
Killed: 26,544 (2003–11)[43]
(4,000 foreign fighters killed by Sep. 2006)[44]
Detainees: 12,000 (Iraqi-held, in 2010 only)[45]
119,752 insurgents arrested (2003–2007)[46]
Total dead: 31,608–37,344

Estimated deaths:
Lancet survey** (March 2003 – July 2006): 654,965 (95% CI: 392,979–942,636)[47][48]
Opinion Research Business**: (March 2003 – August 2007): 1,033,000 (95% CI: 946,258–1,120,000)[49]
Iraq Family Health Survey*** (March 2003 – July 2006): 151,000 (95% CI: 104,000–223,000)[50]
PLOS Medicine Study**: (March 2003 – June 2011): 405,000 (95% CI: 48,000–751,000)
Documented deaths from violence:
Iraq Body Count (2003 – 14 December 2011): 103,160–113,728 civilian deaths recorded[51] and 12,438 new deaths added from the Iraq War Logs[52]
Associated Press (March 2003 – April 2009): 110,600[53]

For more information see Casualties of the Iraq War.
* "injured, diseased, or other medical": required medical air transport. UK number includes "aeromed evacuations".
** Total excess deaths include all additional deaths due to increased lawlessness, degraded infrastructure, poorer healthcare, etc.
*** Violent deaths only – does not include excess deaths due to increased lawlessness, poorer healthcare, etc.

The Iraq War[nb 1] was a protracted armed conflict that began in 2003 with the invasion of Iraq by a United States-led coalition that overthrew 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.[54] An estimated 151,000 to 1,033,000 Iraqis were killed in the first three to four years of conflict. US troops were officially withdrawn in 2011. The U.S. became re-involved in 2014 at the head of a new coalition; the insurgency and many dimensions of the armed conflict continue. The invasion occurred as part of the George W. Bush administration's War on Terror following the September 11 attacks despite no connection of the latter to Iraq.[55]

In October 2002, Congress authorized President Bush to launch a military attack against Iraq.[56] The Iraq War began on 20 March 2003,[57] when the U.S., joined by the U.K. and several coalition allies, launched a "shock and awe" bombing campaign. Iraqi forces were quickly overwhelmed as coalition forces swept through the country. The invasion led to the collapse of the Ba'athist government; Saddam Hussein was captured during Operation Red Dawn in December of that same year and executed three years later. The power vacuum following Saddam's demise and mismanagement by the Coalition Provisional Authority led to widespread civil war between Shias and Sunnis, as well as a lengthy insurgency against coalition forces. Many of the violent insurgent groups were supported by Iran and al-Qaeda in Iraq. The United States responded with a build-up of 170,000 troops in 2007.[58] This build-up gave greater control to Iraq's government and military, and was judged a success by many.[59] In 2008, President Bush agreed to a withdrawal of all U.S. combat troops from Iraq. The withdrawal was completed under President Barack Obama in December 2011.[60][61]

The Bush administration based its rationale for the Iraq War principally on the assertion that Iraq possessed an active weapons of mass destruction (WMD) program,[62] and that the Iraqi government posed a threat to the United States and its coalition allies.[63][64] Some U.S. officials falsely accused Saddam of harbouring and supporting al-Qaeda.[65] In 2004, the 9/11 Commission said there was no evidence of an operational relationship between the Saddam Hussein regime and al-Qaeda.[66] No stockpiles of WMDs or an active WMD program were ever found in Iraq.[67] Bush administration officials made numerous assertions about a purported Saddam-al-Qaeda relationship and WMDs that were based on sketchy evidence, and which intelligence officials rejected.[67][68] The rationale of U.S. pre-war intelligence faced heavy criticism both domestically and internationally.[69] The Chilcot Report, a British inquiry into its decision to go to war, was published in 2016 and concluded military action may have been necessary but was not the last resort at the time and that the consequences of invasion were underestimated.[70] When interrogated by the FBI, Saddam Hussein admitted to having kept up the appearance of possessing weapons of mass destruction in order to appear strong in front of Iran.[71] He also confirmed that Iraq did not have weapons of mass destruction prior to the U.S. invasion.[72]

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 alienated the country's previously dominant Sunni minority and worsened sectarian tensions. In the summer of 2014, the ISIL launched a military offensive in northern Iraq and declared a worldwide Islamic caliphate, leading to Operation Inherent Resolve, another military response from the United States and its allies.

The Iraq War caused at least one hundred thousand civilian deaths, as well as tens of thousands of military deaths (see estimates below). The majority of deaths occurred as a result of the insurgency and civil conflicts between 2004 and 2007. Subsequently, the War in Iraq of 2013 to 2017, which is considered a domino effect of the invasion, caused at least 155,000 deaths, in addition to the displacement of five million people within the country.[73][74][75]

Background

Strong international opposition to the Saddam Hussein regime began after Iraq's invasion of Kuwait in 1990. The international community condemned the invasion,[76] and in 1991 a military coalition led by the United States launched the Gulf War to expel Iraq from Kuwait. Following the Gulf War, the US and its allies tried to keep Saddam Hussein in check with a policy of containment. This policy involved numerous economic sanctions by the UN Security Council; the enforcement of Iraqi no-fly zones declared by the US and the UK to protect the Kurds in Iraqi Kurdistan and Shias in the south from aerial attacks by the Iraqi government; and ongoing inspections to ensure Iraq's compliance with United Nations resolutions concerning Iraqi weapons of mass destruction.

A UN weapons inspector in Iraq, 2002

The inspections were carried out by the United Nations Special Commission (UNSCOM). UNSCOM, in cooperation with the International Atomic Energy Agency, worked to ensure that Iraq destroyed its chemical, biological, and nuclear weapons and facilities.[77] In the decade following the Gulf War, the United Nations passed 16 Security Council resolutions calling for the complete elimination of Iraqi weapons of mass destruction. Member states communicated their frustration over the years that Iraq was impeding the work of the special commission and failing to take seriously its disarmament obligations. Iraqi officials harassed the inspectors and obstructed their work,[77] and in August 1998 the Iraqi government suspended cooperation with the inspectors completely, alleging that the inspectors were spying for the US.[78] The spying allegations were later substantiated.[79]

In October 1998, removing the Iraqi government became official U.S. foreign policy with enactment of the Iraq Liberation Act. The act provided $97 million for Iraqi "democratic opposition organizations" to "establish a program to support a transition to democracy in Iraq."[80] This legislation contrasted with the terms set out in United Nations Security Council Resolution 687, which focused on weapons and weapons programs and made no mention of regime change.[81] One month after the passage of the Iraq Liberation Act, the US and UK launched a bombardment campaign of Iraq called Operation Desert Fox. The campaign's express rationale was to hamper Saddam Hussein's government's ability to produce chemical, biological, and nuclear weapons, but U.S. intelligence personnel also hoped it would help weaken Saddam's grip on power.[82]

Following the election of George W. Bush as president in 2000, the US moved towards a more aggressive Iraq policy. The Republican Party's campaign platform in the 2000 election called for "full implementation" of the Iraq Liberation Act as "a starting point" in a plan to "remove" Saddam.[83] Little formal movement towards an invasion occurred until the 11 September attacks although plans were drafted and meetings were held from the first days of his administration.[84][85]

Pre-war events

After 9/11, the Bush Administration national security team actively debated an invasion of Iraq. On the day of the attacks, Secretary of Defense Donald Rumsfeld asked his aides for: "best info fast. Judge whether good enough hit Saddam Hussein at the same time. Not only Osama bin Laden."[86] President Bush spoke with Rumsfeld on 21 November and instructed him to conduct a confidential review of OPLAN 1003, the war plan for invading Iraq.[87] Rumsfeld met with General Tommy Franks, the commander of U.S. Central Command, on 27 November to go over the plans. A record of the meeting includes the question "How start?", listing multiple possible justifications for a U.S.–Iraq War.[88][89] The rationale for invading Iraq as a response to 9/11 has been widely questioned, as there was no cooperation between Saddam Hussein and al-Qaeda.[90]

Excerpt from Donald Rumsfeld memo dated 27 November 2001 [88]

President Bush began laying the public groundwork for an invasion of Iraq in January 2002 State of the Union address, calling Iraq a member of the Axis of Evil, and saying "The United States of America will not permit the world's most dangerous regimes to threaten us with the world's most destructive weapons."[91] Bush said this and made many other dire allegations about the threat of Iraqi weapons of mass destruction despite the fact that the Bush administration knew that Iraq had no nuclear weapons and had no information about whether Iraq had biological weapons.[92] He began formally making his case to the international community for an invasion of Iraq in his 12 September 2002 address to the UN Security Council.[93] However, a 5 September 2002 report from Major General Glen Shaffer revealed that the Joint Chiefs of Staff's J2 Intelligence Directorate had concluded that the United States' knowledge on different aspects of the Iraqi WMD program ranged from essentially zero to about 75%, and that knowledge was particularly weak on aspects of a possible nuclear weapons program: "Our knowledge of the Iraqi nuclear weapons program is based largely – perhaps 90% – on analysis of imprecise intelligence," they concluded. "Our assessments rely heavily on analytic assumptions and judgment rather than hard evidence. The evidentiary base is particularly sparse for Iraqi nuclear programs."[94][95] Similarly, the British government found no evidence that Iraq possessed nuclear weapons or any other weapons of mass destruction and that Iraq posed no threat to the West, a conclusion British diplomats shared with the U.S. government.[96]

Key U.S. allies in NATO, such as the United Kingdom, agreed with the US actions, while France and Germany were critical of plans to invade Iraq, arguing instead for continued diplomacy and weapons inspections. After considerable debate, the UN Security Council adopted a compromise resolution, UN Security Council Resolution 1441, which authorized the resumption of weapons inspections and promised "serious consequences" for non-compliance. Security Council members France and Russia made clear that they did not consider these consequences to include the use of force to overthrow the Iraqi government.[97] The US and UK ambassadors to the UN publicly confirmed this reading of the resolution.[98]

Resolution 1441 set up inspections by the United Nations Monitoring, Verification and Inspection Commission (UNMOVIC) and the International Atomic Energy Agency. Saddam accepted the resolution on 13 November and inspectors returned to Iraq under the direction of UNMOVIC chairman Hans Blix and IAEA Director General Mohamed ElBaradei. As of February 2003, the IAEA "found no evidence or plausible indication of the revival of a nuclear weapons program in Iraq"; the IAEA concluded that certain items which could have been used in nuclear enrichment centrifuges, such as aluminum tubes, were in fact intended for other uses.[99] In March 2003, Blix said progress had been made in inspections, and no evidence of WMD had been found.[100]

In October 2002, the US Congress passed the "Iraq Resolution", which authorized the President to "use any means necessary" against Iraq. Americans polled in January 2003 widely favored further diplomacy over an invasion. Later that year, however, Americans began to agree with Bush's plan (see popular opinion in the United States on the invasion of Iraq). The US government engaged in an elaborate domestic public relations campaign to market the war to its citizens. Americans overwhelmingly believed Saddam did have weapons of mass destruction: 85% said so, even though the inspectors had not uncovered those weapons. By February 2003, 64% of Americans supported taking military action to remove Saddam from power.[101]

United States Secretary of State Colin Powell holding a model vial of anthrax while giving a presentation to the United Nations Security Council

On 5 February 2003, Secretary of State Colin Powell appeared before the UN to present evidence that Iraq was hiding unconventional weapons. However, Powell's presentation included information based on the claims of Rafid Ahmed Alwan al-Janabi, codenamed "Curveball", an Iraqi emigrant living in Germany who later admitted that his claims had been false.[102] Powell also presented evidence alleging Iraq had ties to al-Qaeda. As a follow-up to Powell's presentation, the United States, the United Kingdom, Poland, Italy, Australia, Denmark, Japan, and Spain proposed a resolution authorizing the use of force in Iraq, but NATO members like Canada, France, and Germany, together with Russia, strongly urged continued diplomacy. Facing a losing vote as well as a likely veto from France and Russia, the US, the UK, Poland, Spain, Denmark, Italy, Japan, and Australia eventually withdrew their resolution.[103][104]

From the left: French President Jacques Chirac, U.S. President George W. Bush, UK Prime Minister Tony Blair and Italian Prime Minister Silvio Berlusconi. Chirac was against the invasion, the other three leaders were in favor.

In March 2003, the United States, the United Kingdom, Poland, Australia, Spain, Denmark, and Italy began preparing for the invasion of Iraq with a host of public relations and military moves. In an address to the nation on 17 March 2003, Bush demanded that Saddam and his two sons, Uday and Qusay, surrender and leave Iraq, giving them a 48-hour deadline.[105]

The UK House of Commons held a debate on going to war on 18 March 2003 where the government motion was approved 412 to 149.[106] The vote was a key moment in the history of the Blair administration, as the number of government MPs who rebelled against the vote was the greatest since the repeal of the Corn Laws in 1846. Three government ministers resigned in protest at the war, John Denham, Lord Hunt of Kings Heath, and the then Leader of the House of Commons Robin Cook.

Opposition to invasion

In October 2002, former U.S. President Bill Clinton warned about possible dangers of pre-emptive military action against Iraq. Speaking in the UK at a Labour Party conference he said: "As a preemptive action today, however well-justified, may come back with unwelcome consequences in the future.... I don't care how precise your bombs and your weapons are when you set them off, innocent people will die."[107][108] Of 209 House Democrats in Congress, 126 voted against the Authorization for Use of Military Force Against Iraq Resolution of 2002, although 29 of 50 Democrats in the Senate voted in favor of it. Only one Republican Senator, Lincoln Chafee, voted against it. The Senate's lone Independent, Jim Jeffords, voted against it. Retired US Marine, former Navy Secretary and future US senator Jim Webb wrote shortly before the vote, "Those who are pushing for a unilateral war in Iraq know full well that there is no exit strategy if we invade."[109]

In the same period, Pope John Paul II publicly condemned the military intervention. During a private meeting, he also said directly to George W. Bush: "Mr. President, you know my opinion about the war in Iraq. Let's talk about something else. Every violence, against one or a million, is a blasphemy addressed to the image and likeness of God."[110]

Anti-war protest in London, September 2002. Organised by the British Stop the War Coalition, up to 400,000 took part in the protest. [111]

On 20 January 2003, French Foreign Minister Dominique de Villepin declared "we believe that military intervention would be the worst solution".[112] Meanwhile, anti-war groups across the world organized public protests. According to French academic Dominique Reynié, between 3 January and 12 April 2003, 36 million people across the globe took part in almost 3,000 protests against war in Iraq, with demonstrations on 15 February 2003 being the largest.[113] Nelson Mandela voiced his opposition in late January, stating "All that (Mr. Bush) wants is Iraqi oil," and questioning if Bush deliberately undermined the U.N. "because the secretary-general of the United Nations [was] a black man".[114]

In February 2003, the US Army's top general, Eric Shinseki, told the Senate Armed Services Committee that it would take "several hundred thousand soldiers" to secure Iraq.[115] Two days later, U.S. Defense Secretary Donald Rumsfeld said the post-war troop commitment would be less than the number of troops required to win the war, and that "the idea that it would take several hundred thousand U.S. forces is far from the mark." Deputy Defense Secretary Paul Wolfowitz said Shinseki's estimate was "way off the mark," because other countries would take part in an occupying force.[116]

Germany's Foreign Secretary Joschka Fischer, although having been in favour of stationing German troops in Afghanistan, advised Federal Chancellor Schröder not to join the war in Iraq. Fischer famously confronted United States Defense Secretary Donald Rumsfeld at the 39th Munich Security Conference in 2003 on the secretary's purported evidence for Iraq's possession of weapons of mass destruction: "Excuse me, I am not convinced!"[117]

There were serious legal questions surrounding the launching of the war against Iraq and the Bush Doctrine of preemptive war in general. On 16 September 2004, Kofi Annan, the Secretary-General of the United Nations, said of the invasion, "I have indicated it was not in conformity with the UN Charter. From our point of view, from the Charter point of view, it was illegal."[118]

The U.S. House of Representatives debating the use of military force with Iraq, 8 October 2002

In November 2008 Lord Bingham, the former British Law Lord, described the war as a serious violation of international law, and accused Britain and the United States of acting like a "world vigilante". He also criticized the post-invasion record of Britain as "an occupying power in Iraq". Regarding the treatment of Iraqi detainees in Abu Ghraib, Bingham said: "Particularly disturbing to proponents of the rule of law is the cynical lack of concern for international legality among some top officials in the Bush administration."[119] In July 2010, Deputy Prime Minister of the UK Nick Clegg, during PMQs session in Parliament, condemned the invasion of Iraq as "illegal" - though he later clarified that this was a personal opinion, not an official one.[120]

2003: Invasion

Destroyed remains of Iraqi tanks near Al Qadisiyah
US Marines escort captured enemy prisoners to a holding area in the desert of Iraq on 21 March 2003.
U.S. soldiers at the Hands of Victory monument in Baghdad

The first Central Intelligence Agency team entered Iraq on 10 July 2002.[121] This team was composed of members of the CIA's Special Activities Division and was later joined by members of the US military's elite Joint Special Operations Command (JSOC).[122] Together, they prepared for an invasion by conventional forces. These efforts consisted of persuading the commanders of several Iraqi military divisions to surrender rather than oppose the invasion, and identifying all the initial leadership targets during very high risk reconnaissance missions.[122]

Most importantly, their efforts organized the Kurdish Peshmerga to become the northern front of the invasion. Together this force defeated Ansar al-Islam in Iraqi Kurdistan before the invasion and then defeated the Iraqi army in the north.[122][123] The battle against Ansar al-Islam, known as Operation Viking Hammer, led to the death of a substantial number of militants and the uncovering of a chemical weapons facility at Sargat.[121][124]

At 5:34 a.m. Baghdad time on 20 March 2003 (9:34 pm, 19 March EST) the surprise[125] military invasion of Iraq began.[126] There was no declaration of war.[127] The 2003 invasion of Iraq was led by U.S. Army General Tommy Franks, under the code-name Operation Iraqi Freedom,[128] the UK code-name Operation Telic, and the Australian code-name Operation Falconer. Coalition forces also cooperated with Kurdish Peshmerga forces in the north. Approximately forty other governments, the "Coalition of the Willing," participated by providing troops, equipment, services, security, and special forces, with 248,000 soldiers from the United States, 45,000 British soldiers, 2,000 Australian soldiers and 194 Polish soldiers from Special Forces unit GROM sent to Kuwait for the invasion.[129] The invasion force was also supported by Iraqi Kurdish militia troops, estimated to number upwards of 70,000.[130]

Iraqi tank on Highway 27 destroyed in April 2003

According to General Franks, there were eight objectives of the invasion:

"First, ending the regime of Saddam Hussein. Second, to identify, isolate, and eliminate Iraq's weapons of mass destruction. Third, to search for, to capture, and to drive out terrorists from that country. Fourth, to collect such intelligence as we can relate to terrorist networks. Fifth, to collect such intelligence as we can relate to the global network of illicit weapons of mass destruction. Sixth, to end sanctions and to immediately deliver humanitarian support to the displaced and to many needy Iraqi citizens. Seventh, to secure Iraq's oil fields and resources, which belong to the Iraqi people. And last, to help the Iraqi people create conditions for a transition to representative self-government."[131]

The invasion was a quick and decisive operation encountering major resistance, though not what the U.S., British and other forces expected. The Iraqi regime had prepared to fight both a conventional and irregular, asymmetric warfare at the same time, conceding territory when faced with superior conventional forces, largely armored, but launching smaller-scale attacks in the rear using fighters dressed in civilian and paramilitary clothes.

Map of the invasion routes and major operations/battles of the Iraq War through 2007

Coalition troops launched air and amphibious assaults on the al-Faw Peninsula to secure the oil fields there and the important ports, supported by warships of the Royal Navy, Polish Navy, and Royal Australian Navy. The United States Marine Corps' 15th  Marine Expeditionary Unit, attached to 3 Commando Brigade and the Polish Special Forces unit GROM, attacked the port of Umm Qasr, while the British Army's 16 Air Assault Brigade secured the oil fields in southern Iraq.[132][133]

The heavy armor of the U.S. 3rd Infantry Division moved westward and then northward through the western desert toward Baghdad, while the 1st Marine Expeditionary Force moved more easterly along Highway 1 through the center of the country, and 1 (UK) Armoured Division moved northward through the eastern marshland.[134] The U.S. 1st Marine Division fought through Nasiriyah in a battle to seize the major road junction.[135] The United States Army 3rd Infantry Division defeated Iraqi forces entrenched in and around Talil Airfield.[136]

With the Nasiriyah and Talil Airfields secured in its rear, the 3rd Infantry Division supported by the 101st Airborne Division continued its attack north toward Najaf and Karbala, but a severe sand storm slowed the coalition advance and there was a halt to consolidate and make sure the supply lines were secure.[137] When they started again they secured the Karbala Gap, a key approach to Baghdad, then secured the bridges over the Euphrates River, and U.S. forces poured through the gap on to Baghdad. In the middle of Iraq, the 1st Marine Division fought its way to the eastern side of Baghdad and prepared for the attack to seize the city.[138]

photograph of three Marines entering a partially destroyed stone palace with a mural of Arabic script
U.S. Marines from 1st Battalion 7th Marines enter a palace during the Fall of Baghdad.

On 9 April, Baghdad fell, ending Saddam's 24‑year rule. U.S. forces seized the deserted Ba'ath Party ministries and, according to some reports later disputed by the Marines on the ground, stage-managed[139] the tearing down of a huge iron statue of Saddam, photos and video of which became symbolic of the event, although later controversial. Allegedly, though not seen in the photos or heard on the videos, shot with a zoom lens, was the chant of the inflamed crowd for Muqtada al-Sadr, the radical Shiite cleric.[140] The abrupt fall of Baghdad was accompanied by a widespread outpouring of gratitude toward the invaders, but also massive civil disorder, including the looting of public and government buildings and drastically increased crime.[141][142]

According to the Pentagon, 250,000 short tons (230,000 t) (of 650,000 short tons (590,000 t) total) of ordnance was looted, providing a significant source of ammunition for the Iraqi insurgency. The invasion phase concluded when Tikrit, Saddam's home town, fell with little resistance to the U.S. Marines of Task Force Tripoli.

In the invasion phase of the war (19 March – 30 April), an estimated 9,200 Iraqi combatants were killed by coalition forces along with an estimated 3,750 non-combatants, i.e. civilians who did not take up arms.[143] Coalition forces reported the death in combat of 139 U.S. military personnel[144] and 33 UK military personnel.[145]

2003–2011: Post-invasion phase

2003: Beginnings of insurgency

A Marine Corps M1 Abrams tank patrols Baghdad after its fall in 2003.
Humvee struck by an improvised explosive device attack in Iraq on 29 September 2004. Staff Sgt. Michael F. Barrett, a military policeman in Marine Wing Support Squadron 373, was severely injured in the attack.
Polish GROM forces in sea operations during the Iraq War
Marines from D Company, 3rd Light Armored Reconnaissance Battalion guard detainees prior to loading them into their vehicle.

On 1 May 2003, President Bush visited the aircraft carrier USS Abraham Lincoln operating a few miles west of San Diego, California. At sunset, he held his nationally televised "Mission Accomplished" speech, delivered before the sailors and airmen on the flight deck. Bush declared the end of major combat operations in Iraq, due to the defeat of Iraq's conventional forces, while maintaining that much still needed to be done.

Nevertheless, Saddam Hussein remained at large, and significant pockets of resistance remained. After Bush's speech, coalition forces noticed a flurry of attacks on its troops began to gradually increase in various regions, such as the "Sunni Triangle".[146] The initial Iraqi insurgents were supplied by hundreds of weapons caches created before the invasion by the Iraqi army and Republican Guard.

Initially, Iraqi resistance (described by the coalition as "Anti-Iraqi Forces") largely stemmed from fedayeen and Saddam/Ba'ath Party loyalists, but soon religious radicals and Iraqis angered by the occupation contributed to the insurgency. The three governorates with the highest number of attacks were Baghdad, Al Anbar, and Saladin. Those three governorates account for 35% of the population, but by December 2006 they were responsible for 73% of U.S. military deaths and an even higher percentage of recent U.S. military deaths (about 80%).[147]

Insurgents used various guerrilla tactics, including mortars, missiles, suicide attacks, snipers, improvised explosive devices (IEDs), car bombs, small arms fire (usually with assault rifles), and RPGs (rocket propelled grenades), as well as sabotage against the petroleum, water, and electrical infrastructures.

Coalition efforts to establish post-invasion Iraq commenced after the fall of Saddam's regime. The coalition nations, together with the United Nations, began to work to establish a stable, compliant democratic state capable of defending itself from non-coalition forces, as well as overcoming internal divisions.[148]

Meanwhile, coalition military forces launched several operations around the Tigris River peninsula and in the Sunni Triangle. A series of similar operations were launched throughout the summer in the Sunni Triangle. In late 2003, the intensity and pace of insurgent attacks began to increase. A sharp surge in guerrilla attacks ushered in an insurgent effort that was termed the "Ramadan Offensive", as it coincided with the beginning of the Muslim holy month of Ramadan.

To counter this offensive, coalition forces began to use airpower and artillery again for the first time since the end of the invasion, by striking suspected ambush sites and mortar launching positions. Surveillance of major routes, patrols, and raids on suspected insurgents was stepped up. In addition, two villages, including Saddam's birthplace of al-Auja and the small town of Abu Hishma, were surrounded by barbed wire and carefully monitored.

Shortly after the invasion, the multinational coalition created the Coalition Provisional Authority (CPA; Arabic: سلطة الائتلاف الموحدة‎), based in the Green Zone, as a transitional government of Iraq until the establishment of a democratic government. Citing United Nations Security Council Resolution 1483 (22 May 2003) and the laws of war, the CPA vested itself with executive, legislative, and judicial authority over the Iraqi government from the period of the CPA's inception on 21 April 2003 until its dissolution on 28 June 2004.

Occupation zones in Iraq as of September 2003

The CPA was originally headed by Jay Garner, a former U.S. military officer, but his appointment lasted only until 11 May 2003, when President Bush appointed L. Paul Bremer. On 16 May 2003, his first day on the job, Paul Bremer issued Coalition Provisional Authority Order 1 to exclude from the new Iraqi government and administration members of the Baathist party. This policy, known as De-Ba'athification, eventually led to the removal of 85,000 to 100,000 Iraqi people from their job,[149] including 40,000 school teachers who had joined the Baath Party simply to keep their jobs. U.S. army general Ricardo Sanchez called the decision a "catastrophic failure".[150] Bremer served until the CPA's dissolution in June 2004.

In May 2003, the US Advisor to Iraq Ministry of Defense within the CPA, Walter B. Slocombe, advocated changing the pre-war Bush policy to employ the former Iraq Army after hostilities on the ground ceased.[151] At the time, hundreds of thousands of former Iraq soldiers who had not been paid for months were waiting for the CPA to hire them back to work to help secure and rebuild Iraq. Despite advice from U.S. Military Staff working within the CPA, Bremer met with President Bush, via video conference, and asked for authority to change the U.S. policy. Bush gave Bremer and Slocombe authority to change the pre-war policy. Slocombe announced the policy change in the Spring of 2003. The decision led to the alienation of hundreds of thousands of former armed Iraq soldiers, who subsequently aligned themselves with various occupation resistance movements all over Iraq. In the week before the order to dissolve the Iraq Army, no coalition forces were killed by hostile action in Iraq; the week after, five U.S. soldiers were killed. Then, on 18 June 2003, coalition forces opened fire on former Iraq soldiers protesting in Baghdad who were throwing rocks at coalition forces. The policy to disband the Iraq Army was reversed by the CPA only days after it was implemented. But it was too late; the former Iraq Army shifted their alliance from one that was ready and willing to work with the CPA to one of armed resistance against the CPA and the coalition forces.[152]

Another group created by the multinational force in Iraq post-invasion was the 1,400-member international Iraq Survey Group, who conducted a fact-finding mission to find Iraq weapons of mass destruction (WMD) programs. In 2004, the ISG's Duelfer Report stated that Iraq did not have a viable WMD program.[153]

Saddam Hussein being pulled from his hideaway in Operation Red Dawn, 13 December 2003

In summer 2003, the multinational forces focused on capturing the remaining leaders of the former government. On 22 July, a raid by the U.S. 101st Airborne Division and soldiers from Task Force 20 killed Saddam's sons (Uday and Qusay) along with one of his grandsons. In all, over 300 top leaders of the former government were killed or captured, as well as numerous lesser functionaries and military personnel.

Most significantly, Saddam Hussein himself was captured on 13 December 2003, on a farm near Tikrit in Operation Red Dawn.[154] The operation was conducted by the United States Army's 4th Infantry Division and members of Task Force 121. Intelligence on Saddam's whereabouts came from his family members and former bodyguards.[155]

With the capture of Saddam and a drop in the number of insurgent attacks, some concluded the multinational forces were prevailing in the fight against the insurgency. The provisional government began training the new Iraqi security forces intended to police the country, and the United States promised over $20 billion in reconstruction money in the form of credit against Iraq's future oil revenues. Oil revenue was also used for rebuilding schools and for work on the electrical and refining infrastructure.

Shortly after the capture of Saddam, elements left out of the Coalition Provisional Authority began to agitate for elections and the formation of an Iraqi Interim Government. Most prominent among these was the Shia cleric Grand Ayatollah Ali al-Sistani. The Coalition Provisional Authority opposed allowing democratic elections at this time.[156] The insurgents stepped up their activities. The two most turbulent centers were the area around Fallujah and the poor Shia sections of cities from Baghdad (Sadr City) to Basra in the south.

2004: Insurgency expands

Footage from the gun camera of a U.S. Apache helicopter killing suspected Iraqi insurgents [157]
Coalition Provisional Authority director L. Paul Bremer signs over sovereignty to the appointed Iraqi Interim Government, 28 June 2004.

The start of 2004 was marked by a relative lull in violence. Insurgent forces reorganised during this time, studying the multinational forces' tactics and planning a renewed offensive. However, violence did increase during the Iraq Spring Fighting of 2004 with foreign fighters from around the Middle East as well as Jama'at al-Tawhid wal-Jihad, an al-Qaeda-linked group led by Abu Musab al-Zarqawi, helping to drive the insurgency.[158]

U.S. troops fire mortars.

As the insurgency grew there was a distinct change in targeting from the coalition forces towards the new Iraqi Security Forces, as hundreds of Iraqi civilians and police were killed over the next few months in a series of massive bombings. An organized Sunni insurgency, with deep roots and both nationalist and Islamist motivations, was becoming more powerful throughout Iraq. The Shia Mahdi Army also began launching attacks on coalition targets in an attempt to seize control from Iraqi security forces. The southern and central portions of Iraq were beginning to erupt in urban guerrilla combat as multinational forces attempted to keep control and prepared for a counteroffensive.

The most serious fighting of the war so far began on 31 March 2004, when Iraqi insurgents in Fallujah ambushed a Blackwater USA convoy led by four U.S. private military contractors who were providing security for food caterers Eurest Support Services.[159] The four armed contractors, Scott Helvenston, Jerko Zovko, Wesley Batalona, and Michael Teague, were killed with grenades and small arms fire. Subsequently, their bodies were dragged from their vehicles by local people, beaten, set ablaze, and their burned corpses hung over a bridge crossing the Euphrates.[160] Photos of the event were released to news agencies worldwide, causing a great deal of indignation and moral outrage in the United States, and prompting an unsuccessful "pacification" of the city: the First Battle of Fallujah in April 2004.

A USMC M198 artillery piece firing outside Fallujah in October 2004

The offensive was resumed in November 2004 in the bloodiest battle of the war: the Second Battle of Fallujah, described by the U.S. military as "the heaviest urban combat (that they had been involved in) since the Battle of Hue City in Vietnam."[161] During the assault, U.S. forces used white phosphorus as an incendiary weapon against insurgent personnel, attracting controversy. The 46‑day battle resulted in a victory for the coalition, with 95 U.S. soldiers killed along with approximately 1,350 insurgents. Fallujah was totally devastated during the fighting, though civilian casualties were low, as they had mostly fled before the battle.[162]

Another major event of that year was the revelation of widespread prisoner abuse at Abu Ghraib, which received international media attention in April 2004. First reports of the Abu Ghraib prisoner abuse, as well as graphic pictures showing U.S. military personnel taunting and abusing Iraqi prisoners, came to public attention from a 60 Minutes II news report (28 April) and a Seymour M. Hersh article in The New Yorker (posted online on 30 April.)[163] Military correspondent Thomas Ricks claimed that these revelations dealt a blow to the moral justifications for the occupation in the eyes of many people, especially Iraqis, and was a turning point in the war.[164]

2004 also marked the beginning of Military Transition Teams in Iraq, which were teams of U.S. military advisors assigned directly to New Iraqi Army units.

2005: Elections and transitional government

Convention center for Council of Representatives of Iraq

On 31 January, Iraqis elected the Iraqi Transitional Government in order to draft a permanent constitution. Although some violence and a widespread Sunni boycott marred the event, most of the eligible Kurd and Shia populace participated. On 4 February, Paul Wolfowitz announced that 15,000 U.S. troops whose tours of duty had been extended in order to provide election security would be pulled out of Iraq by the next month.[165] February to April proved to be relatively peaceful months compared to the carnage of November and January, with insurgent attacks averaging 30 a day from the prior average of 70.

The Battle of Abu Ghraib on 2 April 2005 was an attack on United States forces at Abu Ghraib prison, which consisted of heavy mortar and rocket fire, under which an estimated 80–120 armed insurgents attacked with grenades, small arms, and two vehicle-borne improvised explosive devices (VBIED). The U.S. force's munitions ran so low that orders to fix bayonets were given in preparation for hand-to-hand fighting. It was considered to be the largest coordinated assault on a U.S. base since the Vietnam War.[166]

Hopes for a quick end to the insurgency and a withdrawal of U.S. troops were dashed in May, Iraq's bloodiest month since the invasion. Suicide bombers, believed to be mainly disheartened Iraqi Sunni Arabs, Syrians and Saudis, tore through Iraq. Their targets were often Shia gatherings or civilian concentrations of Shias. As a result, over 700 Iraqi civilians died in that month, as well as 79 U.S. soldiers.

The summer of 2005 saw fighting around Baghdad and at Tall Afar in northwestern Iraq as U.S. forces tried to seal off the Syrian border. This led to fighting in the autumn in the small towns of the Euphrates valley between the capital and that border.[167]

A referendum was held on 15 October in which the new Iraqi constitution was ratified. An Iraqi National Assembly was elected in December, with participation from the Sunnis as well as the Kurds and Shia.[167]

Insurgent attacks increased in 2005 with 34,131 recorded incidents, compared to a total 26,496 for the previous year.[168]

2006: Civil war and permanent Iraqi government

The beginning of 2006 was marked by government creation talks, growing sectarian violence, and continuous anti-coalition attacks. Sectarian violence expanded to a new level of intensity following the al-Askari Mosque bombing in the Iraqi city of Samarra, on 22 February 2006. The explosion at the mosque, one of the holiest sites in Shi'a Islam, is believed to have been caused by a bomb planted by al-Qaeda.

Although no injuries occurred in the blast, the mosque was severely damaged and the bombing resulted in violence over the following days. Over 100 dead bodies with bullet holes were found on 23 February, and at least 165 people are thought to have been killed. In the aftermath of this attack the U.S. military calculated that the average homicide rate in Baghdad tripled from 11 to 33 deaths per day. In 2006 the UN described the environment in Iraq as a "civil war-like situation".[169]

On 12 March, five United States Army soldiers of the 502nd Infantry Regiment raped the 15-year-old Iraqi girl Abeer Qassim Hamza al-Janabi, and then murdered her, her father, her mother Fakhriya Taha Muhasen and her six-year-old sister Hadeel Qassim Hamza al-Janabi. The soldiers then set fire to the girl's body to conceal evidence of the crime.[170] Four of the soldiers were convicted of rape and murder and the fifth was convicted of lesser crimes for their involvement in the events, which became known as the Mahmudiyah rape and killings.[171][172]

Nouri al-Maliki meets with George W. Bush, June 2006

On 6 June 2006, the United States was successful in tracking Abu Musab al-Zarqawi, the leader of al-Qaeda in Iraq who was killed in a targeted killing, while attending a meeting in an isolated safehouse approximately 8 km (5.0 mi) north of Baqubah. Having been tracked by a British UAV, radio contact was made between the controller and two United States Air Force F-16C jets, which identified the house and at 14:15 GMT, the lead jet dropped two 500‑pound (230 kg) guided bombs, a laser-guided GBU‑12 and GPS-guided GBU‑38 on the building where he was located. Six others—three male and three female individuals—were also reported killed. Among those killed were one of his wives and their child.

The government of Iraq took office on 20 May 2006, following approval by the members of the Iraqi National Assembly. This followed the general election in December 2005. The government succeeded the Iraqi Transitional Government, which had continued in office in a caretaker capacity until the formation of the permanent government.

The Iraq Study Group Report was released on 6 December 2006. The Iraq Study Group made up of people from both of the major U.S. parties, was led by co-chairs James Baker, a former Secretary of State (Republican), and Lee H. Hamilton, a former U.S. Representative (Democrat). It concluded that "the situation in Iraq is grave and deteriorating" and "U.S. forces seem to be caught in a mission that has no foreseeable end." The report's 79 recommendations include increasing diplomatic measures with Iran and Syria and intensifying efforts to train Iraqi troops. On 18 December, a Pentagon report found that insurgent attacks were averaging about 960 attacks per week, the highest since the reports had begun in 2005.[173]

Coalition forces formally transferred control of a governorate to the Iraqi government, the first since the war. Military prosecutors charged eight U.S. Marines with the murders of 24 Iraqi civilians in Haditha in November 2005, 10 of them women and children. Four officers were also charged with dereliction of duty in relation to the event.[174]

Saddam Hussein was hanged on 30 December 2006, after being found guilty of crimes against humanity by an Iraqi court after a year-long trial.[175]

2007: U.S. troops surge

President George W. Bush announces the new strategy on Iraq from the White House Library, 10 January 2007.

In a 10 January 2007, televised address to the U.S. public, Bush proposed 21,500 more troops for Iraq, a job program for Iraqis, more reconstruction proposals, and $1.2 billion for these programs.[176] On 23 January 2007, in the 2007 State of the Union Address, Bush announced "deploying reinforcements of more than 20,000 additional soldiers and Marines to Iraq".

On 10 February 2007, David Petraeus was made commander of Multi-National Force – Iraq (MNF-I), the four-star post that oversees all coalition forces in country, replacing General George Casey. In his new position, Petraeus oversaw all coalition forces in Iraq and employed them in the new "Surge" strategy outlined by the Bush administration.[177]