Rachel Maddow did an hour long special called Hubris: Selling the Iraq War that is exactly the kind of investigative journalism that the cable news networks should be doing more often. I was glad that she began with the Tonkin resolution, which was the lie on which the Vietnam war was based. The war in Iraq was started on no less audacious a set of lies. You can watch the whole thing here.
The recurring theme is the Bush administration repeatedly declaring that they had evidence that the intelligence services either disputed or explicitly rejected. Dick Cheney, Condoleeza Rice and George W. Bush himself went on television over and over again and said that they had convincing evidence either of a link between Saddam Hussein and Al Qaeda or of his possession of WMDs and an active program to develop chemical, biological or nuclear weapons. In each and every case, that evidence was either highly disputed or already known to be false and unreliable.
The Iraq war was sold on the basis of a lie. No, of a whole bushel full of lies.