Despite United Nations Security Council Resolution 1441 in 2002 demanding compliance, no UN mandate authorized an armed attack. Consequently, the US formed the "Coalition of the Willing" alongside 45,000 British, 2,000 Australian, and 200 Polish troops, launching Operation Iraqi Freedom on March 20, 2003. Overwhelming air and ground superiority led to the fall of Baghdad on April 9, 2003. President Saddam Hussein went into hiding before being captured in December 2003 and executed in 2006 under Iraq's newly established government. Post-invasion searches revealed no WMD stockpiles, and the power vacuum precipitated years of sectarian warfare, claiming hundreds of thousands of lives and costing the US over $3 trillion. An 8-year direct occupation transitioned into anti-insurgency and counter-ISIS support roles, culminating in the final military exit on September 30, 2026.