Nuclear weapons played a triple role in the edification of Raymond Aron's intellectual work : obviously in the comments he made and positions he adopted inside the nuclear strategic debate from 1945 to 1983, but also in the genesis of his theory of international relations and of war (culminating in the Paix et guerre and in Penser la guerre, Clausewitz), and lastly in is personal biography as a "commited observer" of the French and transatlantic strategic debates