In their aftermath, the U.S. invaded Afghanistan, swiftly deposing the Taliban regime that had been sheltering Osama bin Laden, the leader of the al-Qaida terror network blamed for the attacks.
But it was not long before President George W. Bush shifted his attention to Iraq, identifying it, along with Iran and North Korea, as part of an "axis of evil" and asserting that its brutal dictator, Saddam Hussein, was armed with weapons of mass destruction and had ties to al-Qaida. No evidence of either was found.
What followed was a U.S.-led invasion of a country in the heart of the Middle East that spurred a decade of war, with consequences that reverberate across the region to this day.
"At first, I was happy with the U.S. invasion, everyone was happy. We were filled with hope for a better future," said Mohammed Agha, an Iraqi Kurd who was 27 when the invasion began.
"But then what happened was that the country's institutions were destroyed and never rebuilt again," he said. "There was no planning for the day after and no nation-building."
The Iraq War was a protracted armed conflict from 2003 to 2011 that began with the invasion of Iraq by the United States–led coalition which overthrew the authoritarian government of Saddam Hussein. The conflict continued for much of the next decade as an insurgency emerged to oppose the coalition forces and the post-invasion Iraqi government. An estimated 151,000 to 1,033,000 Iraqis died in the first three to five years of conflict. US troops were officially withdrawn in 2011. The United States 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.
In October 2002, Congress granted President Bush the power to decide whether to launch any military attack in Iraq. The Iraq War began on 20 March 2003, when the US, joined by the UK, Australia, and Poland 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. This build-up gave greater control to Iraq's government and military, and was judged a success by many. In 2008, President Bush agreed to a withdrawal of all US combat troops from Iraq. The withdrawal was completed under President Barack Obama in December 2011.
The Bush administration based its rationale for the Iraq War on the claim that Iraq had a weapons of mass destruction program, and that Iraq posed a threat to the United States and its allies. Some US officials falsely accused Saddam of harbouring and supporting al-Qaeda. In 2004, the 9/11 Commission said there was no evidence of an operational relationship between the Saddam Hussein regime and al-Qaeda. No stockpiles of WMDs or an active WMD program were ever found in Iraq. Bush administration officials made numerous claims about a purported Saddam–al-Qaeda relationship and WMDs that were based on sketchy evidence, and which intelligence officials rejected. The rationale for war faced heavy criticism both domestically and internationally. Kofi Annan called the invasion illegal under international law as it violated the UN Charter. The Chilcot Report, a British inquiry into its decision to go to war, was published in 2016 and concluded peaceful alternatives to war had not been exhausted, that the United Kingdom and the United States had undermined the authority of the United Nations Security Council, that the process of identifying the legal basis was 'far from satisfactor'y, and that the war was unnecessary. When interrogated by the FBI, Saddam Hussein confirmed that Iraq did not have weapons of mass destruction prior to the US invasion.
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, 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 . 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 and occupation, caused at least 155,000 deaths, in addition to the displacement more than 3.3 million people within the country.
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.' 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. Rumsfeld met with General Tommy Franks, the commander of US 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 US–Iraq War. 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.
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.' 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. 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. 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.' 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 US government.
Key US 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. The US and UK ambassadors to the UN publicly confirmed this reading of the resolution.
Resolution 1441 set up inspections by the United Nations Monitoring, Verification and Inspection Commission 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. In March 2003, Blix said progress had been made in inspections, and no evidence of WMD had been found.
In October 2002, the US Congress passed the 'Iraq Resolution', which authorized the President to 'use any means necessar'y 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 . 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.
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. 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.
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. 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. The vote was a key moment in the history of the Blair government, 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.