Ronnie “Stray Dog” Hall scared the bejesus out of me when he played the backwoods drug lord Thump Milton in Debra Granik’s Winter’s Bone (2010), but in this vivid documentary profile by Granik, he’s as sweet as can be. The proprietor of a Missouri trailer park, the grizzled, portly biker learns Spanish from a computer program so he can converse with his Mexican wife, but he devotes the lion’s share of his time to Vietnam POW-MIA activism and still wrestles with his own savagery during the war (“When he dreams, his conscience churns inside him,” his wife says). Family issues take over the narrative: Stray Dog’s grown daughter from another union announces that she’s pregnant, and the biker and his wife arrange for her teenage sons to immigrate from Mexico City. This is Granik’s first documentary, and it lacks the momentum of her two dramatic features (the other is the gripping addiction drama Down to the Bone with Vera Farmiga). But it’s still a worthwhile bulletin from red-state America.