Admit it: For years you've been burning to know what Phyllis Diller really thinks about electric cars, which first (dis)appeared in her youth. "They were very quiet," she recalls. The real question is why this purportedly impassioned documentary investigation of a great subject—American culture's conspiratorial dismissal of eco-friendly alternatives to the gas-guzzler—would assume such massive viewer disinterest that it coats the pill with C-list celebrity NutraSweet, including Martin Sheen voice-overs that would sound unforgivably hackneyed even on basic cable. An opening vignette in a California cemetery has GM's produced-and-abandoned EV-1 being "buried" by tearful mourners; subsequent title cards finger so many of the usual suspects (carmakers, lawmakers, big oil, us) that the titular question might as well be Who Didn't Kill . . . ? Director Chris Paine's choice of talking heads leads you to think that famous people were the only ones lucky enough to have leased GM's now-flattened roadster. Another few of these squandered opportunities for art-house muckraking and we'll need someone to ask who killed the left-wing documentary.