Diplomacy is the art and practice of conducting negotiations between representatives of groups or states. It usually refers to international diplomacy, the conduct of international relations through the intercession of professional diplomats with regard to issues of peace-making, trade, war, economics and culture. International treaties are usually negotiated by diplomats prior to endorsement by national politicians. Many world leaders (though not all) are skilled in the art of diplomacy. As monarchs, characters such as Aquaman and Queen Hippolyta have had to use their diplomatic skills to maintain peace within their respective kingdoms of Atlantis and Themyscira. Most U.S. Presidents have nurtured this skill as well including Franklin Delano Roosevelt, Pete Ross and Jonathan Horne. Pete Ross' predecessor however, Lex Luthor, was not particularly known for his diplomacy, though he did successfully lead the country during the Imperiex war.