The Iraq War, also known as the Second Persian Gulf War, the Occupation of Iraq, or  Operation Iraqi Freedom, is an ongoing military campaign which began on March 20, 2003 with the invasion of Iraq by a multinational force now led by and composed almost entirely of troops from the United States and United Kingdom.

Prior to the war, the governments of the U.S. and U.K claimed that Iraq's alleged possession of weapons of mass destruction (WMD) posed an imminent threat to their security and that of their coalition allies.  United Nations weapons inspectors found no evidence of WMD, giving support to earlier criticism of poor intelligence on the subject. After the invasion, the U.S.-led Iraq Survey Group concluded that Iraq had ended its WMD 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 for which the coalition invaded. Some U.S. officials also accused Saddam Hussein of harboring and supporting Al-Qaeda but no evidence of any collaborative relationship was ever found. Other reasons for the invasion stated by U.S. officials included Iraq's financial support for the families of Palestinian suicide bombers, Iraqi government human rights abuses, and an effort on the part of the coalition forces to spread democracy in the country and region. Some officials said Iraq's oil reserves were a factor in the decision to invade, but other officials denied this.

The invasion of Iraq led to an occupation and the eventual capture and execution of Saddam Hussein. Violence against coalition forces and among various sectarian groups soon led to asymmetric warfare with the Iraqi insurgency, strife between many Sunni and Shia Iraqi groups, and al-Qaeda operations in Iraq. The number of Iraqis killed through 2007 ranges from "a conservative cautious minimum" of more than 85,000 civilians to a survey estimate of more than 1,000,000 citizens. UNHCR estimates the war uprooted 4.7 million Iraqis through April 2008 (about 16% of the population of Iraq), two million of whom had fled to neighbouring countries fleeing a humanitarian situation that the Red Cross described in March 2008 as "among the most critical in the world". In June 2008, U.S. defense officials claimed security and economic indicators began to show signs of improvement in what they hailed as significant and fragile gains. In August 2008, Iraq was fifth on the Failed States Index.

Member nations of the Coalition withdrew their forces as public opinion favoring troop withdrawals increased and as Iraqi forces began to take responsibility for security. In late 2008, the U.S. and Iraqi governments approved a Status of Forces Agreement effective through January 1, 2012.The Iraqi Parliament also ratified a Strategic Framework Agreement with the U.S., aimed at ensuring international cooperation in constitutional rights, threat deterrence, education, energy development, and other areas. In late February 2009, U.S. President Barack Obama announced an 18-month withdrawal window for "combat forces", leaving behind 30,000 to 50,000 troops "to advise and train Iraqi security forces and to provide intelligence and surveillance". General Ray Odierno, the top U.S. military commander in Iraq, said he believes all U.S. troops will be out of the country by the end of 2011, while British forces ended combat operations on April 30, 2009. Iraqi Prime Minister Nouri al-Maliki has said he supports the accelerated pullout of U.S. forces.

2001–2003: Iraq disarmament crisis and pre-war intelligence

See also: Lead up to the Iraq War, Rationale for the Iraq War, Public relations preparations for 2003 invasion of Iraq, Governments' pre-war positions on invasion of Iraq, Saddam Hussein and al-Qaeda, 10 Days to War, and Iraq and weapons of mass destruction
Main articles: Iraq disarmament crisis timeline 2001-2003 and 2002 in Iraq
According to documents provided by former Treasury Secretary Paul O'Neill, George W. Bush instructed his aides to look for a way to overthrow the Iraqi regime ten days after taking office in January 2001. A secret memo entitled "Plan for post-Saddam Iraq" was discussed in January and February 2001, and a Pentagon document dated March 5, 2001, and entitled "Foreign Suitors for Iraqi Oilfield contracts", included a map of potential areas for exploration.

U.N. weapons inspections resume

The issue of Iraq's disarmament reached a crisis in 2002-2003, when President Bush demanded a complete end to alleged Iraqi production of weapons of mass destruction and full compliance with UN Resolutions requiring UN weapons inspectors unfettered access to suspected weapons production facilities. Previously, the UN had prohibited Iraq from developing or possessing such weapons after the Gulf War and required Iraq to permit inspections confirming compliance.
During 2002, Bush repeatedly backed demands for unfettered inspection and disarmament with threats of military force. In accordance with UN Security Council Resolution 1441 Iraq reluctantly agreed to new inspections in late 2002. The results of these inspections were mixed, with the inspectors discovering no WMD programs but concluding that Iraqi declarations failed to prove that all such weapons had been properly destroyed.

Alleged weapons of mass destruction

In the initial stages of the war on terror, the Central Intelligence Agency (CIA), under George Tenet, was rising to prominence as the lead agency in the Afghanistan war. But when Tenet insisted in his personal meetings with President Bush that there was no connection between Al Qaeda and Iraq, Vice-President Dick Cheney and Secretary of Defense Donald Rumsfeld initiated a secret program to re-examine the evidence and marginalize the CIA and Tenet. A major part of this program was a Pentagon unit known as the Office of Special Plans (OSP), which was created by Deputy Secretary of Defense Paul Wolfowitz and headed by Douglas Feith. It was created to supply senior Bush administration officials with raw intelligence pertaining to Iraq, unvetted by intelligence analysts, and circumventing traditional intelligence gathering operations by the CIA. The questionable intelligence acquired by the OSP was "stovepiped" to Cheney and presented to the public. In some cases, Cheney’s office would leak the intelligence to news correspondents, who would in turn cover it in such outlets such as The New York Times. Cheney would subsequently appear on the Sunday political television talk shows to discuss the intelligence, referencing The New York Times as the source to give it credence.

Ambassador Joseph C. Wilson

Prior to the Gulf War, in 1990, Iraq had stockpiled 550 short tons (500 t) of yellowcake uranium at the tha nuclear complex about 20 kilometres (12 mi) south of Baghdad. In late February 2002, the CIA sent former Ambassador Joseph Wilson to investigate reports that Iraq was attempting to purchase additional yellowcake from Niger. Wilson returned and informed the CIA that reports of yellowcake sales to Iraq were "unequivocally wrong." The Bush administration, however, continued to allege Iraq's attempts to obtain additional yellowcake were a justification for military action - most prominently in the January, 2003 State of the Union address when President Bush said that Iraq had sought uranium, citing British intelligence sources.  In response, Wilson wrote a critical New York Times op-ed piece in June 2003 stating that he had personally investigated claims of yellowcake purchases and believed them to be fraudulent. After Wilson's op-ed, Wilson's wife was publicly identified as an undercover CIA analyst Valerie Plame in a column. This led to a Justice Department investigation into the source of the leak. On May 1, 2005 the "Downing Street memo" was published in The Sunday Times. It contained an overview of a secret July 23, 2002 meeting among British government, Ministry of Defence, and British intelligence figures who discussed the build-up to the Iraq war — including direct references to classified U.S. policy of the time. The memo stated, "Bush wanted to remove Saddam, through military action, justified by the conjunction of terrorism and WMD. But the intelligence and facts were being fixed around the policy."

On September 18, 2002, George Tenet briefed Bush that Saddam Hussein did not have weapons of mass destruction. Bush dismissed this top-secret intelligence from Saddam's inner circle which was approved by two senior CIA officers, but it turned out to be completely accurate. The information was never shared with Congress or even CIA agents examining whether Saddam had such weapons. The CIA had contacted Saddam Hussein's foreign minister, Naji Sabri, who was being paid by the French as an agent. Sabri informed them that Saddam had ambitions for a nuclear program but that it was not active, and that no biological weapons were being produced or stockpiled, although research was underway.

In September 2002, the Bush administration, the CIA and the DIA said attempts by Iraq to acquire high-strength aluminum tubes, which were prohibited under the UN monitoring program, pointed to a clandestine effort to make enriched uranium for nuclear bombs. This analysis was opposed by the United States Department of Energy (DOE) and INR which was significant because of DOE's expertise in gas centrifuges and nuclear weapons programs. The DOE and INR argued that such tubes were poorly suited for centrifuges. An effort by the DOE to change Colin Powell's comments before his UN appearance was rebuffed by the administration. Indeed, Powell, in his address to the UN Security Council just prior to the war, made reference to the aluminum tubes. But a report released by the Institute for Science and International Security in 2002 reported that it was highly unlikely that the tubes could be used to enrich uranium. Powell later admitted he had presented an inaccurate case to the United Nations on Iraqi weapons, and the intelligence he was relying on was, in some cases, "deliberately misleading." Shortly after the United States presidential election, 2008, and the election of rival Democratic party nominee Barack Obama, president Bush admitted that "my biggest regret of all the presidency has to have been the intelligence failure in Iraq.
source: http://en.wikipedia.org/wiki/War