Winner of this year's Best Documentary Oscar, Errol Morris' film gives the floor to former US Defence Secretary Robert S McNamara for 106 punchy, pertinent minutes.
Though in his mid-eighties, he shows scant sign of marble-loss, lucid and lively as he reflects on World War Two, Presidents Kennedy and Johnson and the bloody foul-up that was 'Nam. It's all yoked together by 11 lessons on matters military, McNamara hitting notes that resonate loudly in the current climate: "If we can't persuade nations of comparable values of the rightness of our cause, then we'd better re-examine our reasoning."
Doubling up as off-camera interviewer, Morris keeps the eye as busy as the ear, whisking in jump-cuts, skewed framing and choice archive footage. Perhaps the documaker could have given the old boy a tougher grilling, but he teases out more than enough to make this an essential sermon on 20th-century history.