The realist theory posits that since humans are predisposed to disagreements, conflict is inevitable in human affairs. All states strive for survival in such an anarchic world and thus it is national interests that reign supreme rather than ethics, morals and ideals. Doyle has very aptly put it that “International anarchy precludes the effective escape from the dreary history of war and conflict that are the consequence of competition under anarchy”.
Such a competition entails state to state relations where the necessity in warfare is never about inevitability but about probability and risks. States weigh the probability and risks and the possible ‘costs-benefits’ for going to war. At the core of any nation’s national interest lies its security and survival. The international system is a sort of ‘self help’ system where the state that perseveres in efforts to strengthen itself achieves greater security. In pursuance of this core national interest, states strive to achieve economic prosperity which enables them to build up military might that in turn acts as a guarantor of their survival.
Power, thus is a key constituent in a realist outlook. Power confers the endowed state an ability to control the behavior of other states. In realist terms, such a power whether it is in the form of imperialism, traditional hegemony or extra-regional hegemony is an attribute that enhances the national security of a country. The realist school seeks for primacy of a state over other states. When there is parity among powers it leads to stability and then these powers prevent the rise of other powers to maintain stability and ensure their respective national security. This is called as the ‘Balance of Power’ theory, a subset of the realist theory of national security which has numerous offshoots.