The United States is back at war—that didn’t take very long. One might argue we never really stopped fighting, or, frankly, that the country has been in a perpetual state of war since World War II. Religious as well as the more generic popular responses to America’s various wars often boils down to a tension between revulsion and obligation. Not surprisingly, that dualism relates directly to the simple formula presidents have used over the years (and through every war) to justify military actions in strategic and moral terms. The threats change—fascism, communism, terrorism—as do the locations, but the moral rationale rarely does.