Debra Granik's Leave No Trace is as principled as the movement that shares the film's title -- a worldwide community committed to minimal impact while enjoying the wilderness.
In the first 15 minutes of this film, a father, Will, and daughter, Tom, (Ben Foster and Thomasin Harcourt McKenzie, both splendid) are shown in their "home," a camp in a woodsy public park in Portland, Oregon, where they forage off the grid, undetected and undisturbed.
Dad, a war veteran who appears plagued by PTSD, runs his daughter through drills that are to help the girl elude those wanting to disturb the peace. He's decent and loving; she is unspoiled and obedient. They are hurting no one.
Of course, the peace is disrupted; father and daughter are discovered, detained and relocated to a tree farm where the owner (Jeff Kober) lets them live in exchange for Dad's labor. It's not long before the two are off again; Dad's anxieties will not let him be. Granik's film is loaded with dread but blessedly free of belligerence.
Yes, the distress in it is heartbreaking but it's so elegantly written and finely tuned that the viewer's anguish is triggered not by rage but by a simple line spoken by a young girl, bone tired of running and hoping that finally her father's demons might be quieted: "I like it here."