Thirteen years ago, Samantha Power made a name for herself with her Pulitzer prize-winning book, “‘A Problem from Hell’: America and the Age of Genocide.” In this book, she explored the history of America’s reluctance to intervene to stop or prevent genocides. Prescribing American intervention as justified on grounds both “moral” and in service of “enlightened self-interest,” Power asked how something so clear in retrospect as the need to stop genocide could “become so muddled at the time by rationalization, institutional constraints, and a lack of imagination.” It appears that on Monday morning, Power herself is going to demonstrate exactly...