MAIN IDEA OF REALISM, LIBERALISM AND CONSTRUCTIVISM Realism is the interpretation that world politics is motivated by competitive self-interest. Realists then believe that the significant dynamic among states is a struggle for power in an exertion to preserve or, if possible, expand its army security and economic benefit in competition with other states. Moreover, realists perceive this battle for power as a zero-sum game, in which an achievement for one state is certainly a loss for others. Realists are also possible to perceive humanity as integrally shared by national commitment to states or other identity for example culture or religion. In the words realists define national interest mainly in terms of whatever enhances or preserves a state 's security, influence, and its military and economic power. This does not mean that realists are amoral (Williams, 2004). Some argue that the highest moral duty of the state is to do good for its citizens while other realists argue that surviving in a dangerous world requires that morality be weighed wisely against national interest. There are many implications to the realists ' dark view of politics. One is that there is little hope for substantially reforming the anarchic international system. Second, realpolitik holds that countries should practice balance-of-power politics. This means to strive to achieve an equilibrium of power in the world in order to prevent any other country or coalition of countries from dominating the