ts believe that the state is the primary actor in the international world and that those states are inherently preoccupied with the balance of power; specifically, the balance of military power and the use of military force. As a result, realism tends to focus on issues relating to the use of force. For example, a realist would likely construct analysis relating to deterrence and war fighting, and the impact of nuclear weapons on international politics (Mearsheimer http://globetrotter.berkeley.edu).
According to Realist John J. Mearsheimer (http://globetrotter.berkeley.edu) in an interview with Harry Kreisler of the Institute of International Studies at UC Berkeley, there are three types of realists. The first type of realist is the "human nature realist," who believes that "states, like individuals, are hardwired at birth with a will to power in them, and that states constantly compete for power, because it's an innate phenomenon" (Mearsheimer http://globetrotter.berkeley.edu). He cites Hans Morganthau as the most famous Human Nature Realist.
The second type of realism can be characterized as Defensive Realism, as constructed by the preeminent international relations theorist and "Defensive Realist," Kenneth Waltz. Defensive realism asserts that states behave somewhat aggressively because the structure of the international system forces them to compete for power and the best way to survive in the system is to be very powerful. Every state understands that, and, therefore, they compete for power. An example of this theory is perfectly illustrated in how the United States and the Soviet Union behaved during the Cold War (Mearsheimer http://globetrotter.berkeley.edu).
An important element to Defensive Realism, however, is that it also asserts that states only want a limited amount of power because too much power is a bad thing and so, it does not make sense to want too much power (Mearsheimer http://globetrotter.berkeley.e...