ABSTRACT
For Hobbes and his contemporaries, the major source of reflection on the relations between states came from the natural law tradition is that, the tradition of moral theology, strongly influenced by Christianity, which we have already seen at work in Leviathan's description of the state of nature. Natural law thus provided the backbone of the seventeenth-century study of what we now call international relations. Along with liberalism and Marxism, realism is often identified as one among three traditional schools of thinking about international relations. The realist school explains international relations by the self-interest of the actors involved, usually sovereign states or combinations of them. Liberals incline to see the international arena as being at least partly regulated by legal instruments and international bodies like the UN. Game theory has played a major part in modern attempts by international relations theorists to explain conflict.
