On ASERI's thirtieth anniversary, Michael Cox reflects on the lessons of history and why great powers rise and fall. Taking up Paul Kennedy's analysis in The Rise and Fall of the Great Powers (1987), he recalls that empires do not collapse out of weakness, but because of "imperial overextension". After the apparent unipolar triumph of the United States in the nineties, wars, economic crises and the return of geopolitical competition have cracked the liberal model. Today, between global challenges such as artificial intelligence, climate and demographic transition, power appears increasingly unstable and shared. ASERI, in thirty years of activity, has taught us to read history as a set of recurring dilemmas and to understand power with critical rigor and ethical responsibility.