The debate between the Neorealists and the Neoliberals emerged in the 1970s and developed over the next two decades into the major theoretical controversy within IR. Waltz himself contributed to the classical level of Realism with his 'Man, the State and War' (1959), which described Morgenthau's and Carr's treatment of IR as a never-ending series of conflicts among states trapped in a condition of anarchy. Twenty years later, Waltz published his 'Theory of International Politics' (1979) in which he sought to explain the causes of war. The structural realism is captured in the concept of the balance of power. This system is one where we need to focus our attention because its constituent units perform the same functions in the system, regardless of where they are located, their ideology and culture. Waltz argues that bipolar systems are more stable than multipolar systems. According to him, in International Relations the idea of the system is all important.