Final answer:
The United States invaded Iraq in 2003 to eliminate Saddam Hussein's regime, disarm alleged WMDs, and counter terrorism threats. Lack of evidence for WMDs and interests in Iraqi oil resources led to controversy and scrutiny of the war's motivations.
Step-by-step explanation:
The United States invaded Iraq in 2003 with the primary rationale of removing Iraqi leader Saddam Hussein from power, preventing the use of alleged weapons of mass destruction (WMDs), and reducing the potential threat of terrorism. After the September 11 attacks, there was a heightened focus on national security, and Iraq was suspected of possessing WMDs. Despite UN weapons inspectors not confirming their existence, the U.S. administration, led by President George W. Bush, proceeded with the invasion. Additional factors included geopolitical interests, such as oil contracts with Western companies, and a precedent of conflict with Iraq, particularly the Gulf War in 1990. Eventually, it was recognized that Iraq did not have WMDs, and the U.S. faced challenges in stabilizing the country post-invasion, leading to significant loss of life and questioning the true motivations for the war.