The US invaded Iraq based of the manipulation of information by some parts of George W Bush administration, with officials like National security adviser John Bolton, Press Secretary Ari Fleischer, and Vice President D*ck Cheney lying to the people and Congress saying that Iraq had weapons of mass destruction which they didn't have. so in 2003 the senate voted and approved the war using the 2001 war powers allowing the US to attack anyone found responsible for 9/11 which was especially controversial because Iraq had not aided or participated in 9/11