Iraq was much different. Our own military full on bombed and then occupied it. Iraq was also sold on a "pre-emptive" doctrine where Ukraine is (disingenuously) framed as defensive. Iraq hinged on the ideas that Saddam had WMDs and was harboring terrorists. 9/11 was instrumental in engineering fear about terrorism. The most charitable thing I could reasonably believe about 9/11 is that they knew and let it happen anyway because it was politically useful.