Amarillo Sheriff Olmstead (R. Lee Ermey) is in the political fight of his life. Chief McGinnis (William Fichtner) is his strongest opponent in years, and both men are eager for anything which might give them a boost of visibility in the upcoming election. They get it when a serial killer strikes, killing a couple in a local motel.
Olmstead happily accepts the assistance of lone FBI agent Frank LaCrosse (Dennis Quaid), who mysteriously appears on the scene, and seems to know more about the killer than he hesitantly reveals.
However, two likely suspects have banded together and headed out of town, toward Colorado. Lane Dixon (Jared Leto) is a mysterious wanderer who has been placed at the scene of the crime. Bob Goodall (Danny Glover) is creepily idiosyncratic (he drives around in a car whose inside is laminated with naked women), and shows a prodigous talent with a hunting knife.
The film is somewhat schizophrenic as it switches back and forth between the two storylines. At first, there's no indication of the link between the Amarillo serial killer and the westward journey of Lane and Bob. However, the film segues between the two often enough, that it becomes obvious that either Lane or Bob is the killer. (Even though the film perplexingly tosses out a completely unrelated red herring in its opening scenes).
Dennis Quaid is remarkably flat in his role as the lone FBI crusader, showing little to no emotion throughout the film. His blandness is highlighted by the dynamic performance of R. Lee Ermey as the county sheriff. Quaid offers such little support, that it is up to Glover and Leto to carry the main plot thread. They do alright. However, the central dillema about their characters is resolved roughly halfway through the movie. Then, they're forced to bide time to the end.
The killer in SwitchBack lacks the depth of the great villains in Silence of the Lambs, Seven, or even the lesser ones in Kiss the Girls and Copycat. He's given no motive and much of what he does is inexplicable. He appears to be far from the great challenge that has led the FBI halfway across the country.
At least the cinematography on SwitchBack is well done, making the most of its picturesque Colorado locations. Its action scenes (primarily its climactic fight) are interesting, and would have been more so if you cared one iota about the characters involved.
Still, although it is a watchable film, it suffers heavily from its flaws. With the lack of a strong performance by Dennis Quaid (the only character who stands to unify both plots of the film), and the lack of a strong script to bring all the threads together, SwitchBack is a failure.