At the end of World War I, Iraq became a British-mandated territory. When it was declared independent in 1932, the Hashemite family, which also ruled Jordan, ruled as a constitutional monarchy. In 1945, Iraq joined the United Nations and became a founding member of the Arab League. In 1956, the Baghdad Pact allied Iraq, Turkey, Iran, Pakistan, and the United Kingdom, and established its headquarters in Baghdad.

Gen. Abdul Karim Qasim took power in July 1958 coup, during which King Faysal II and Prime Minister Nuri as-Said were killed. Qasim ended Iraq's membership in the Baghdad Pact in 1959. Qasim was assassinated in February 1963, when the Arab Socialist Renaissance Party (Ba'ath Party) took power under the leadership of Gen. Ahmad Hasan al-Bakr as prime minister and Col. Abdul Salam Arif as president.

Nine months later, Arif led a coup ousting the Ba'ath government. In April 1966, Arif was killed in a plane crash and was succeeded by his brother, Gen. Abdul Rahman Mohammad Arif. On July 17, 1968, a group of Ba'athists and military elements overthrew the Arif regime. Ahmad Hasan al-Bakr reemerged as the President of Iraq and Chairman of the Revolutionary Command Council (RCC).

In July 1979, Bakr resigned, and Saddam Hussein assumed both offices. The Iran-Iraq war (1980-88) devastated the economy of Iraq. Iraq declared victory in 1988 but actually achieved a weary return to the status quo antebellum. The war left Iraq with the largest military establishment in the Gulf region but with huge debts and an ongoing rebellion by Kurdish elements in the northern mountains. The government suppressed the rebellion by using weapons of mass destruction on civilian targets, including a mass chemical weapons attack on the city of Halabja that killed several thousand civilians.

Iraq invaded Kuwait in August 1990, but a U.S.-led coalition acting under United Nations (UN) resolutions expelled Iraq from Kuwait in February 1991. After the war, the UN Security Council required the regime to surrender its weapons of mass destruction (WMD) and submit to UN inspections. When the Ba'ath regime refused to fully cooperate with the UN inspections, the Security Council employed sanctions to prevent further WMD development and compel Iraqi adherence to international obligations. Coalition forces enforced no-fly zones in southern and northern Iraq to protect Iraqi citizens from attack by the regime and a no-drive zone in southern Iraq to prevent the regime from massing forces to threaten or again invade Kuwait.

A U.S.-led coalition removed the Ba'ath regime in March and April 2003, bringing an end to more than 12 years of Iraqi defiance of UN Security Council resolutions. The coalition, international agencies, and nongovernmental organizations quickly established aid systems, preventing any general humanitarian crisis. The coalition formed the Coalition Provisional Authority (CPA) to provide for the administration of Iraq during the period of transitional administration, restore conditions of security and stability, and create conditions in which the Iraqi people can freely determine their own political future. The UN Security Council acknowledged the authorities of the coalition and provided for a role for the UN and other parties to assist in fulfilling these objectives.

The CPA disbanded on June 28, 2004, transferring sovereign authority for governing Iraq to the Iraqi Interim Government (IIG). Based on the timetable laid out in the Transitional Administrative Law (TAL), the IIG governed Iraq until elections were held on January 30, 2005; thereafter the Iraqi Transitional Government assumed authority.