Stephen Martin Walt (born July 2, 1955) is an American political scientist currently serving as the Robert and Renee Belfer Professor of international relations at the Harvard Kennedy School.A member of the realist school of international relations, Walt has made important contributions to the theory of neorealism and has authored the balance of threat theory. Books that he has authored or coauthored include Origins of Alliances, Revolution and War, and The Israel Lobby and U.S. Foreign Policy. Source: Wikipedia (en)