It came up recently in another thread:
http://www.internationalskeptics.com/forums/showthread.php?postid=1619855#post1619855
Here's a shortened version of what I said in that thread.
McGovern gave an interview in Feb. 2004, where he talks about Tenet, Bush, 9/11, and the Iraq war:
http://www.nathancallahan.com/mcgovern.html
He made some wrong predictions about Tenet, based in part on what he thought was Tenet's ability to blackmail Bush with a smoking gun in the form of the infamous August 2001 Presidential Daily Briefing. That PDB was released a few months later, and while it may not look that great for Bush, it sure as hell isn't the smoking gun that McGovern thought it would be. According to Tricky, McGovern said in a CNN interview with Anderson Cooper that there are memos which prove Bush knew there were no WMD's in Iraq. I doubt McGovern has even seen whatever memos he's refering to, and is probably just as mistaken about whatever their content is. So he's not exactly a reliable source about what's really going on.
But from a strategic standpoint, the problem with backing McGovern goes even deeper. McGovern also thinks that the war in Iraq was waged for the benefit of Israel, by people in the administration who are more loyal to Israel than to the US. He's also rabidly partisan, referring to neocons as fascists, and comparing 9/11 to the Reichstag fire under Hitler. He's basically fallen into the cliche of what an ultra-leftist anti-war protester should be (compare Bush to Hitler, blame it on the Jews, rant about conspiracy theories, etc) - even if any of his criticisms turn out to be valid, he's exactly the sort of person you DON'T want making your case for you, because a lot of people are going to discount him because he's a wingnut. And you don't even need him to make any case against Bush OR Rumsfeld, because frankly, there is NO new information he's actually bringing to the table. All he represents is argument from authority (the press loves to trot out how he was in the CIA for 27 years, etc), but that won't hold up long under scrutiny. Don't back the loon just because he's the enemy of your enemy. That didn't work out for the anti-war crowd with Cindy Sheehan, and it won't work with McGovern.