I'm not sure if this is the documentary... but it includes interviews with actual CIA and intelligence officials who guit under the Bush Administration because they felt the information was being trumped up to the American people to justify war.
http://www.pbs.org/wgbh/pages/frontline/shows/longroad/
While the world suspected Saddam of developing WMDs... there wasn't a single nation that could make the case that Saddam actually had them. The Bush Administration trumped up falsified data and sold it to the international community to garner support for the invasion of Iraq. Colin Powell was used as a tool and he knows it. That's why Powell refuses to support those neocon warmongers.