Abstract
In 1970 Liberalism tried to create a revolution: international relations should be thought of using the study of economic interdependence, a key concept where states are affected by decisions taken by others. Robert Keohane and Joseph Nye insisted on economic facts of the early 1970s as the crisis of the international monetary system, the oil shocks... Until the 1970s the economy was not an important subject in the study of international relations. Since this period the rise of international political economy brought new outlooks to the study of international relations. The realist family, firstly concentrated on the military power, and then tried gradually to focus on economic effects. Thus, there is a new formulation of realism during the 80s where the main objective is to think about change. This new point of view tries to think moderate change in order to consider cooperation between States. The balance of power is still the essential tool for some realists like Kenneth Waltz or Stephen Walt who think the stability of the international system thanks to a multipolar world.
