Errol Morris's new documentary about the low-ranking "bad apples" who were charged with various forms of prisoner abuse at Abu Ghraib isn't exactly revelatory. You've already read the facts, and the photographs that shocked the entire world (the hooded figure standing on a box, the dusty piles of naked prisoners, a dead man on ice) are burned into your retinas. What the film does, admirably, is pose the questions that up until now had been purely, purposefully rhetorical: Who would commit such a heinous act? And why in the world would you photograph it?

Standard Operating Procedure argues that Sabrina Harman, at least, thought she was collecting evidence. In these interviews, Harman is pretty and sane—at least in comparison with a much older-looking Lynndie England, jilted by the sadistic father of her child, and Megan Ambuhl, who apparently thought it was a good idea to get married to England's man, even after he landed in prison for 10 years. In letters home to her long-term lesbian partner, seen in her original hand, Harman explains her escalating unease with the way prisoners are treated. Unfortunately, she wants to be liked too badly to do anything about it.

The film has drawn criticism because Morris paid his subjects for their interviews, possibly influencing their stories, but at least he doesn't seem to pressure his subjects to deflect blame upward, as director Rory Kennedy did in Ghosts of Abu Ghraib (Kennedy also paid her subjects). The numerous reenactments in the film have also sparked some controversy, but the distinct look of those shots and the frequent use of slow motion make it clear that these images portray only one hypothetical version of events. Standard Operating Procedure is a fascinating, if limited, glimpse at the small personalities that handed the United States its greatest humiliation in decades.