Christian political theology deals with the problems of the ultimate questions: the existence of God and the application of His law in the realm of human relations. Through exploring the political theology of Augustine, Thomas Aquinas, and Reinhold Niebuhr, this study discusses the great issues of war and peace, the character of human nature, the necessity of political responsibility, the importance of moral choices, the functions of authority, and the meaning of history and progress. It argues that Christian realism withstands the serious critiques leveled against it, provided that the complementary strengths and weaknesses of these three figures is taken into account.