If the North Atlantic Treaty Organization (NATO) did not exist today, the United States would not seek to create it. In 1949, it made sense in the face of a potential Soviet invasion to forge a bond in the North Atlantic area among the United States, Canada, and the west European states. Today, if the United States were starting from scratch in a world of transnational threats, the debate would be over whether to follow liberal and neoconservative calls for an alliance of democracies without regard to geography or to develop a great power concert envisioned by the realists to uphold the current order.