Foreign diplomats enjoyed the sight of our moralistic young nation undergoing linguistic gymnastics in order to claim that right always supported its national interest. But larger issues were at stake, and they are the subject of a new book, John Witt’s Lincoln’s Code. It’s worth revisiting these legal conundrums not only because they’re interesting, but also because they take us back to the origins of a codified law of war, and raise still-pertinent questions about the usefulness of having such laws. The law of war has played a central role in debates about American policies toward al-Qaida under Presidents Bush and Obama, with critics frequently arguing that the U.S. government has violated the law of war or improperly cited it as support for its policies. Witt’s historical account helps explain why both administrations felt it necessary to deviate from a strict interpretation of international law.