TWIN FALLS, IDAHO As 7 p.m. approaches, the high-desert sunlight lingers with a golden hue and 80 degree warmth, favoring the people who pull their vehicles into the downtown lot by the Lamphouse Theater. Disembarking and filing into the movie theater, they appear to be a Western cross-section: carefully stepping gray-haired ladies, a guy in an electric wheelchair, a few sweet little girls, the vice mayor, a toddler clinging to a mother’s shoulder, two doctors, and the inevitable guy wearing camo pants. Collectively, they would seem to have little to worry about. All around them on this mid-June evening, Twin...