Ultimately more watchable than illuminating, this feature-length, Oscar-winning interview with 87-year-old Robert S. McNamara, secretary of defense for presidents Kennedy and Johnson, is a masterpiece of hemming and hawing for both its subject and filmmaker Errol Morris. Its most impressive achievement may be its power to convince us that we’re actually thinking (as opposed to brooding) along with McNamara, an effect achieved by Philip Glass’s throbbing score, rapid montages of charts and figures we aren’t supposed to understand, and intertitles of 11 platitudinous lessons that structure and punctuate McNamara’s musings. Among the highlights are McNamara’s suggestions that he’d be regarded as a war criminal had the U.S. lost World War II, that the American commitment to Vietnam was a mistake, and that he was less responsible for the military escalation than Johnson. He also, poor guy, can’t remember whether or not he authorized dropping Agent Orange on North Vietnam. PG-13, 95 min.