A profound understanding of American foreign policy depends upon a thorough and a rigorous theoretical understanding of the ideology that stimulates and determines it. Liberalism claims that spreading liberal democracy across the world can be accomplished through an open international economy and international institutions that promote peace in the international system. Throughout his mainly theoretical contribution, John Mearsheimer argues that on the contrary, liberal democracy harms the U.S. and the international system. For him, liberal democracy leads America to become a highly militarized state fighting unceasing wars. In his preface, Mearsheimer maintains that since 1989 American foreign policy, or what he calls “liberal hegemony,” has been destined to fail. He proposes that we can understand this failure by considering the interactions between liberalism, nationalism and realism, and how they affect international politics. Accordingly, Mearsheimer posits that assessing the relations between these “isms” provides the best pattern for illuminating the failure of American foreign policy.