The paper deals with that part of Norberto Bobbio’s thought related to international relations. Lacking a single comprehensive work of Bobbio, two main themes - war and democracy - are taken as points of departure. The paper considers, first, the role of war in international politics, and the change brought about by the advent of nuclear weapons. Then, it analyzes what the role of democracy in the international system is, showing how Bobbio is keenly aware of the importance of the interaction of external and internal factors in shaping (and studying politics). The thought of Bobbio is constantly compared and contrasted with that of another eclectic thinker of the twentieth century, Raymond Aron. From the comparison, besides some notable differences, a common «dissatisfied» or «heterodox» realist vision emerges. Attention to the great thinkers of the past, to the great themes of international political theory, and the attemp to offer a dispassionate analysis of reality are shared features of their thinking ethics which is a cornerstone of modern democracy.