It’s one of those stories you’d never buy as fiction, but you have to believe because it actually happened — in 1988, Chilean dictator Augusto Pinochet, under pressure from his backers in the U.S. government, held a referendum on his rule of the nation. And thanks to an effective advertising campaign for the “No” side, he lost and subsequently surrendered power.

If only the Oscar-nominated “No,” starring Gael Garcia Bernal as a visionary ad man, had the subversive juice and creative thinking that its real-life hero did. It’s a perfectly fine movie, but given its fairly radical storyline, the filmmaking tends to hew toward the safe and the familiar.

We meet René Saavedra (Garcia Bernal) as he’s promising a roomful of clients a bold vision of the new Chile — and it’s an ad for soda pop, packed with hip teens (and a mime, inexplicably) at a rock concert. When Pinochet announces that the opposing side will get 15 minutes of uncensored airtime every night (unheard of in a country with a state-run media) to make their case, it’s René who gets the gig.

And a good thing, too, since the coalition of Chile’s lefty political groups collectively thinks that there’s no way they can actually win the plebiscite. They’d rather use the 15 minutes to expose Pinochet’s grotesque human rights violations. René disagrees, thinking that the “No” side could actually win, but only with an ad campaign that stresses happiness and positivity. (“I don’t want an anthem,” he tells a composer, “I want a jingle.”)

It’s a David and Goliath tale for the mass-media age -- as one government collaborator observes, the “No” partisans get 15 minutes, while the “Yes” supporters get 15 minutes…and the rest of the programming day -- but “No” relies too heavily on ideas that are intended to be satirical and outrageous.

Is anyone surprised at the thought of political advertising being as shallow and distracting as a campaign for a breakfast cereal or a hygiene product? When René packs his spots, which never mention Pinochet directly, with images of horseback rides in sun-dappled meadows and smiling families on a picnic, we’re supposed to find all this somehow subversive, but the idea of politicians being just another product is at least as old as television itself.

There’s not all that much that “No” has to say that we haven’t already seen in films like “A Face in the Crowd” and “Network” (or on TV’s “Mad Men”), and the subplots about René and his collaborators being shadowed and intimidated by Pinochet’s secret police feel like the stuff of every political thriller you’ve ever seen. A storyline regarding René’s pining for his ex-wife Verónica (Antónia Zegers) doesn’t resonate all that much either, despite Garcia Bernal’s best forlorn-puppy-dog faces whenever she’s around.

Still, the ads themselves (presumably based on the real thing) are fun to watch, and “No” never lags, keeping its true-life tale of a coup via commercials constantly moving forward. Like the successful ad campaigns it champions, the movie is entertaining but ultimately disposable.