What US Government decision was the most impactful on the War in Iraq?

In March 2003, U.S. forces invaded Iraq vowing to destroy Iraqi weapons of mass destruction (WMD) and end the dictatorial rule of Saddam Hussein. When WMD intelligence proved illusory and a violent insurgency arose, the war lost public support. Saddam was captured, tried, and hanged and democratic elections were held.

A Gallup poll made on behalf of CNN and USA Today concluded that 79% of Americans thought the Iraq War was justified, with or without conclusive evidence of illegal weapons. 19% thought weapons were needed to justify the war.

Why did US go to war in Iraq?

The US claimed the intent was to remove "a regime that developed and used weapons of mass destruction, that harbored and supported terrorists, committed outrageous human rights abuses and defied the just demands of the United Nations and the world".

payments were made after the 1940s.

in the 1980s, a commission held investigations and made recommendations.