Christian realism is a foreign policy perspective that originated with Reinhold Niebuhr, the famous moral theologian and public intellectual who was really a titanic figure on the American scene from the 1930s into the 1960s. The essence of Christian realism—which is very much at odds with anything that smacks of utopianism—is to appreciate that there is evil in the world to which we must respond but also to appreciate that our own motives are likely to be less pure than we may fancy them to be. It’s not simply that the motives of the other guys are suspect but we ourselves should always be mindful of the extent to which our own motives [may] be subject to question.
Andrew Bacevich