The recent history of the international system is undoubtedly marked by the end of bi-polarism, which has been regarded as the single most important event in the second half of the 20th century. This “transformational moment”, however, is questioned by a number of historiographical approaches emphasizing the importance of long term trends to understand a number of current events. The course will investigate the evolution of international relations since the end of the cold war by comparing these explicative paradigms. On the one hand, it will look at some of the most distinctive features of the post Cold War era, inlcuding the crises of the 1990s, the emergence of the United States as a hegemonic power, and the consequences of the terrorist attacks of 9/11 and of the 2003 Iraq war on the American ability to preserve its supremacy. On the other, it will discuss different conceptual and chronological frameworks to present the evolution of the international system from more complex perspectives, by looking at long term phenomena such as the return of China to a great power role or the discontinuity introduced in the international system by the Neo-liberal approach since the 1970s.