Tim Blake Nelson's Leaves of Grass is a textbook example of a promising movie that takes a wrong turn from which it never recovers.
Starting well, building good will, assembling a solid farce framework, Nelson's script suddenly abandons all the comedic promises it makes in the first half and turns into a blood-drenched and sadistic action film. It's like grafting the last half of Death Wish on to a stoner comedy (which, come to think of it, describes the similarly uneven - but much funnier - Pineapple Express).
Edward Norton plays twins in this story: Bill, a fast-rising academic star on the faculty of an Ivy League college; and Brady, a similarly prodigious pot farmer in Oklahoma. Bill has escaped his trailer-trash upbringing to transform himself into a teaching whiz in the classics department and has all but disavowed his heritage.
Brady, on the other hand, is a free-swinging weed cultivator, known for the quality of his product and in deep debt to the local crime boss. In this case, it's an Oklahoma City businessman named Pug Rothbaum (Richard Dreyfuss), who keeps his drug dealings on the down-low because he's also a bigwig at his synagogue.
Pug wants Brady to help him deal harder drugs, in exchange for forgiving Brady's outstanding debt. Brady, however, has strict standards about these things. Sure, he runs his own hydroponic facility and reaps the benefits of reefer - but he's got scruples when it comes to more addictive substances.
So he hatches a scheme, one that involves bumping off Pug - and using his twin brother Bill as an alibi. So he lures Bill back to Oklahoma by concocting a crisis, involving their mother (Susan Sarandon, wasted in a nothing role). Then Brady talks Bill into pretending to be him, seen around the small-town where Brady lives, while the real Brady sneaks up to OKC to get out from under Pug's thumb.
You can see it all coming, all the things that might have been: the mistaken-identity humor, the slamming doors, the slapstick. There are so many potentially big laughs, just waiting to be harvested.
Then, in a single moment of realistic and brutal violence, Nelson steers the film into a blind alley - and the movie never recovers. Suddenly, this is a film about drug violence, which escalates dramatically - but not comedically. It's as if the comedy of the first half of the film has been forgotten - or the final two reels of some other, less-interesting film have accidentally been spliced on to a film you were enjoying.
How does a movie like this suddenly and irrevocably go so totally wrong? All you can do is shake your head in wonder and melancholy, at what might have been and what it turned out to be instead. Norton's performance - both of them - winds up being wasted, as do the energetic work of Dreyfuss, Keri Russell (as Bill's love interest) and Nelson himself.
It's sad, really. If things were the other way around - a wrong-headed beginning that builds to a kick-ass third act - the movie might have been redeemed. As it is, Leaves of Grass starts out strong and winds up DOA, trapped in a web of its own making from which it never escapes.