Errol Morris must have thought that it would be a real coup to do a documentary about Donald Rumsfeld, just as it was when he got Robert McNamara to confess his doubts and mistakes during Vietnam in The Fog of War. To make The Unknown Known, Rumsfeld agreed to be interviewed for more than 30 hours in front of Morris' specially rigged Interrotron camera. But when you see the movie, you'll know why: Donald Rumsfeld is a man who likes to hear himself talk. That, after all, was the ultimate message of those realpolitik Zen koans (''Stuff happens,'' ''Osama bin Laden is either alive and well or alive and not too well or not alive'') he dropped in his Iraq-war press conferences. He was making his prankish obfuscations the real story, a gambit the press mocked but also fell for.
In The Unknown Known, Rumsfeld prattles on, quoting from the thousands of ''memos'' he churned out like notes to be stuck in fortune cookies during his tenure in Washington. The memos are stray thoughts, directives, and random bits of Rumsfeldiana; the film's message seems to be that in corrupt governments, words are used not to communicate but as a kind of fascist confetti. Yet to take the playfully convoluted, semi-nonsensical aggression of Rumsfeld's language and make it the whole point of a movie is to fall into the trap of mistaking the spin for the story. (Also available on iTunes and VOD) B-