According to realists, the world has fallen into anarchy because there is no governing body. States are primary actors in the international arena. They are only engaged with one another to maintain power and safety. Classical Realism is the main type of realism. Classical Realists insist that human nature determines state behavior, including cooperation. The classical realists believe that people have a selfish and hostile nature and that this is reflected in the behaviour of the states. Hans Morgenthau was a influential classical realist. He wrote in Politics Among Nations how “politics depends on objective laws which are rooted in the human nature”. Morgenthau believed that the human condition is flawed and conflict occurs when nations seek to gain power. It is inevitable that this will lead to conflict and war. Iraq was a prime example of this inability to cooperate. Sadam Hassan, the dictator of Iraq at the time of the invasion of Kuwait, pursued expansionist policy to ensure his survival and to counter offensive states.

Neo-realists care more about the balance between power and the international arena. The international system structure, they argue, can determine how states behave in the global arena. The states would be in a state anarchy, and could do what they please. This lack in cooperation is explained by the realist view that states are motivated to maximize their power and safety. A goal of survival that maximizes security can be a catalyst to cooperation. Military alliances could be used by smaller states, but also larger ones with greater hegemony to form a military cooperation. Security dilemma is a realist theory that states can’t trust each other and therefore, forming alliances will lead to further conflict. John H. Herz describes the security paradox as “the idea that in a situation of uncertainty, states may feel insecure and take actions to strengthen their capabilities to deal with perceived external threats” (real or fictitious).

When a state feels threatened by another’s military power or alliances, they will feel insecure. This leads to an increase in military capability which, in turn causes the original state to feel the same way, leading to a perpetual cycle of competition. States are unable to work together because they are constantly in fear. India and Pakistan’s current relationship, which has been fraught with conflict and suspicion since 1947 after the partition of British India. To achieve state cooperation, states must trust eachother and resolve the security problem. Despite this, history has shown that even if countries reach agreements on cooperation, they are not guaranteed to be implemented without the help of international institutions. Hitler’s invasion into Russia when he violated Nazi-Soviet agreements was an example. Defensive Realists, on the other hand, argue that this may not always be true. As there is better understanding between the two countries, it makes them more likely to collaborate. The liberal theory also supports this, stating that states who harmonize their interests are more likely to cooperate. US and UK have shown this throughout their history, even when they were not coerced by international institutions. Realists may believe that the international system does not promote conflict, but rather cooperation.