Realists and Neoliberal Institutionalists have radically different views on the role played by international regimes in international politics. While neoliberal institutionalists believe that role is great, realists believe that institutions do not effect the actions of states. The fundamental disagreement concerns whether institutions promote cooperation. Each perspective paints a rather different picture of the world. One picture is grim and portrays states as paranoid self-interested actors. The other perspective stipulates that states are self-interested but are willing to interact with each other under the right conditions. According to the institutionalists these are the conditions the international regimes create.
In "The False Promise of International Institutions" John Mersheimer states the " institutionalist theories is largely a response to realism, and each directly challenges realism's underlying logic- This implies that institutionalism is a reply to realism. Realists dispute the claim that institutions promote stability. Instead, they argue that states are self-interested actors who are constantly trying to become stronger and take advantage of other states. States are constantly improving their security, which is their number one concern. According to realists interactions between states are inhibited by the fear of cheating. Institutionalists respond that this fear can be reduced by presence of institutions. Realists disagree with this point. According to realists institutions are controlled by hegemons. These strong states arrange the regime according to their interests. The hegemon controls what goes on in the regime and controls the states in it. In other words institutions are ways for the larger states to control the weaker states, and to maximize their relative position in international politics. Realists credit balance of power politics for controlling state relations.