According to US President Joe Biden, America’s commitment to the North Atlantic Treaty Organization is “sacred.” To be fair, NATO has proved to be one of the most enduring multilateral military alliances in history. Yet the mission it was designed for, to defend Western Europe from a Soviet invasion during the Cold War, has been over for decades. Like most bureaucracies, however, NATO did not go away when it had helped to achieve an astonishingly bloodless victory in the Cold War. Instead, like most bureaucracies, it mutated and expanded. The Soviet threat was gone after the Cold War, yet the...