Subject Coordinator: Dr Surin Maisrikrod Present by： Yizhi Cao 12657488
Introduction
The earlier international relations history can be tracked back to 1648 of the Peace Treaty of Westphalia. It is a milestone that marks the beginning of the modern state system development. Stanley Hoffman once remarked that international relations theory is both an old and young discipline1. The study of international relations theory was start after the World War I, the University of Wales firstly set up the international relations chairs in 1919 was generally considered to be a sign of discipline building international relations. The purpose of studying international relations theory is try to explain the occurrence of interaction among nations and expectations for the future movement, many theories were established and discovered from that time, and using it to analysis international events. With many scholars working on international relations theory, there are three most popular theories came out which are Realism, Liberalism and Constructivism. Theories of international relations are necessary when people trying to figure out the occurred events, because these theories will help many scholars to analysis international relations under a theoretical framework. The issue of terrorist attack was closely linked with national behaviour body, therefore people wants to understand what is terrorism have to understand it through international relations theories.
Realism
The word Realism was from 19th century German realistic political word which is Realpolitik, however there are a lot of primary assumptions have been expressed from the earlier literatures. For example, an ancient Greek historian Thucydides who wrote the History of the Peloponnesian War has cited as an intellectual forbearer of Realpolitik2. In Thucydides views that Realism as a traditional theory of international relations has become the mainstream point of international politics from the 20th century and developed from WW I and WW II. Realism basically is to oppose the liberalism and deny the cooperation between the states.
Realism theory is based on some key assumptions found out through many years of research by scholars; it is clearly express to people what is realism. One of them is only the sovereign state is the main actor in international systems, all the actions made by the state leader is target on their own security and exists. There are many non-states actors in the international systems such as the multinational corporation, the terrorist group and other multinational and international organizations or NGO as well, but in realist views, to compared with sovereign state the status of the non-state actors always be in the secondary place, states is the one take the dominant position.
Realism emphasizes that states exist in an anarchic environment therefore states need rely on themselves for survival and protect their nation interests so that realists believed that national power especially military forces is the best protection of the nation security. Based on pessimism of human nature, international politics actually is conflict. In realistic thinking people are selfish, self-interested and competitive everyone is concern about their own benefits in the competition and aspire to become the dominant. This view has reflected in the international relations theory by Hans Morgenthau. As he presented, politics is a battle for all people of the struggle for power, whatever the ultimate goal, power is the direct goal, obtain, maintain, and show of power pattern determines the political behaviour skills3. Basically, the key words of realism are power, security and national interests.
However, it is necessary to understand the advantages and disadvantages of realism. Back to the History of the Peloponnesian War from Thucydides, he found that the Greek world is made up of
