Rather a mess, this one is.
Our central character is Steve (Matt Damon), who works for a natural gas company (they're called "Global," so you know they're Evil). Steve and Sue (Frances McDormand) go around to small towns where shale gas deposits have been found, and buy leases on all the farms in preparation for fracking.
Everything seems to be going just fine in this week's Midwestern village, until the local high school teacher (Hal Holbrook) turns out to be a retired PhD with a lot of questions about the potential danger, and the town is suddenly visited by an environmental activist (John Krasinski) with scare stories about the damage Global's fracking has done elsewhere.
The movie has no faith in its audience's ability to deal with the complexities of the fracking debate. It is simply assumed that because Damon is the corporate guy, he is wrong, and that environmentalist Krasinski must be on the side of the angels. (His character is named Dustin Noble, for god's sake, just in case we hadn't figured out where to put the black and white hats.)
The only argument Damon is ever seen presenting is that of money: Your town and these farms are dying anyway, whether there's fracking or not, so why not cash in on your land before that happens? And we are assumed to be so stupid that the anti-fracking argument is literally reduced to the level of a 9-year-old, as we watch Krasinski talk to an elementary school class.
And since we aren't allowed or encouraged to actually deal with the ideas of the debate, the conflict is reduced to Damon and Krasinski battling for the hearts and minds of the farmers on the strength of their own charm and charisma -- their own movie star power, essentially. And even with the story slanted as badly as it is -- Damon, the evil corporate shill, vs. Krasinski, the lovable doofus environmentalist -- in the battle of charisma, Krasinski is sadly outgunned.
Krasinski's B-team status most seriously cripples the movie in its climactic plot twist, when the true depths of Global's conniving are revealed; it leads to a confrontation that is less charged than it should be because Krasinski doesn't have the chops to go against Damon.
There is some nice work in supporting roles. McDormand is entertaining, particularly in her scenes with Titus Welliver, who plays a local shopkeeper ("Rob's Gas, Guns, Groceries, and Guitars") who flirts with her. Rosemarie DeWitt, always a welcome presence, is handed an underwritten character whose sole purpose is to plunk herself between Damon and Krasinski for the obligatory romantic rivalry, but she gives the character great warmth and more depth than is on the page.
But the movie's refusal to genuinely engage with its own subject matter, and the good-vs-evil simplicity of its characters (which is not sufficiently atoned for by the Big Plot Twists at the end), keep Promised Land from ever becoming more than the ecological equivalent of a Lifetime movie of the week.