Introduction: George Kennan states: "Morality in the method of government, as a matter of conscience and preference on the part of our people - yes." He goes on to state that morality as a criterion for measuring and comparing the behavior of states is flawed. Morality is a preference, not a requirement for governing in the anarchic international system, Kennan argues. Ethics and justice in the international system are measured by how states meet different moral requirements. These moral requirements are defined by a variety of schools of thought, including: realists, state moral theorists, and cosmopolitans. Realists can validate some actions in which the morality of state theorists and cosmopolitans is fundamentally opposed. In this article I will examine such examples and detail the key differences between realists, morality state theorists, and cosmopolitans. I will compare and contrast realists with the other two non-realist perspectives and explore how these theories apply to an international system of states and how these theories shape how a state acts or reacts in an anarchic system. Realists: Kennan, a notable realist, argued that morality should be the foundation of civic virtue and a condition for successful democracy. He also argued that morality is a preference on the part of people. He distances himself from non-realist theorists when he argues that morality has no place in measuring or comparing states to each other: “Here no other criterion, sadder, more limited, more practical, must be able to prevail.” The principles of realists, fundamentally, are that states should act in their own self-interest and that states in the world must focus on their own survival. Realists argue that we live in an anarchic system, and as such… half of the paper… theories outlined in this paper. One of the fundamental principles of realism is that the state is fundamental to everything else, including morality. Realists argue that deviation from state interests in an anarchic system creates vulnerability. State morality theorists support state sovereignty and argue that intervention is not permitted unless circumstances are gross and justify action. They speak of aggression as the only crime that one state can commit against another and suggest that aggression should only be permitted as a retaliatory measure. Finally, cosmopolitans believe that morality can be achieved on an individual level and that morality can be somewhat universally applied. Nonrealists do not support preventative action or intervention under virtually any condition, and the criteria by which intervention is justified are consistent with principles of justice.