  In the fourth principle, Morgenthau considers the relationship between realism and ethics. He says that while realists are aware of the moral significance of political action, they are also aware of the tension between morality and the requirements of successful political action. “Universal moral principles,” he asserts, “cannot be applied to the actions of states in their abstract universal formulation, but …they must be filtered through the concrete circumstances of time and place” (9). These principles must be accompanied by prudence for as he cautions “there can be no political morality without prudence; that is, without consideration of the political consequences of seemingly moral action” (ibid.).