At the end of the Second World War, nuclear weapons immediately became a privileged topic of study for the nascent discipline of International Relations (RI). Within it, the realist school has attempted to integrate nuclear weapons into a general strategic reflection on the evolution of interstate foreign policy. So deeply indeed that, according to a common opinion, a kind of fusion occurred between the realist paradigm and nuclear power : in short, "defending" nuclear deterrence would mean making profession of realism. However, the link between realism and nuclear power is more complex than is commonly thought. To grasp its nuances, it is probably necessary to draw a parallel between the concrete and practical evolution of the Western military nuclear doctrines, on the one hand, and, on the other hand, the theoretical and conceptual positions taken by realistic politicians from 1945 to the present day. It is the object of this article, which aims to recall the articulations between the realistic thought of the IR and the nuclear fact, in order to put them in historical perspective, so as to suggest that the "interlocking web of thought " that is realism, far from being monolithic, has had – and continues to have - multiple nuclear facets.