"Promised Land" is a movie you want to root for all the way. All-American poster boys Matt Damon and John Krasinski star and co-wrote the script, based on a story by Pulitzer finalist Dave Eggers. Supporting player Frances McDormand has never taken a wrong turn onscreen and just keeps getting better.

The story, pitting small-town Davids against a corporate Goliath over fracking, couldn't be more topical. Fearless director Gus Van Sant, whose wide-ranging oeuvre runs from "Drugstore Cowboys" to "Milk," can helm just about anything.

As icing on the built-in conflict, the anti-fracking science teacher is played by a rheumy-eyed Hal Holbrook, the noblest, sweetest-faced octogenarian in the business.

Too bad a preachy tone seeps in and poisons the water.

Recently promoted Steve Butler (Damon) rolls into McKinley, a money-strapped farm town, with cynical colleague Sue (McDormand). They stock up on native-disguise supplies, such as flannel shirts, at a general store selling "guns, groceries, guitars and gas."

Their employer, Global Cross Power Solutions (generic name = sinister motive), hopes to leverage the aw-shucks grin of Butler, a former country boy who nonetheless can't drive a stick shift, into a quick buy-up of land. The plan is hydraulic fracturing, a natural gas drilling process that can contaminate surrounding soil and water and is much in the news at present.

Enter Krasinski's cheeky environmental activist, Dustin Noble (seriously?), who ambles onstage during karaoke night to tip off the townsfolk.

The charm contest is on to see which of the handsome dudes with clashing agendas can win over both comely local gal Alice (Rosemarie DeWitt) and the desperate farmers, many of whom are eager to turn a blind eye to pollution in favor of cash windfalls.

"You all see it coming and you don't get out of the way," preaches Butler of the inevitable change coming -- until he starts to have a change of heart himself. That Butler would have such an epiphany after years as a soulless salesman stretches credulity, despite Damon's persuasive skills.

From there, overt moralizing overwhelms what could have been a nuanced message. Even though Van Sant probably isn't laying it on any thicker than, say, the Jessica Lange "We're staying" speech in the farm-auction drama "Country," it somehow feels heavier and less convincing here. A soundtrack of relentlessly earnest folk music doesn't help.

On the surface, "Promised Land" has a lot in common with the superb '80s indie hit "Local Hero," in which a Texas oil executive with Scottish roots is sent to buy up a seaside town in Scotland for its rich reserves. Instead, he becomes enchanted with the town's way of life.

But that film resisted patronizing its audience and wouldn't have been caught dead including a line like, "What do I do in a world where no one cares?"

What you do is follow one of the oldest writing lessons around -- show, don't tell.

Kristin Tillotson • 612-673-7046