As early as 1985, he specialized in analysis of irregular wars (Indochina, Algeria, etc.) and the first developments of the nuclear weapon under the French Fourth Republic, as well as in the study of the different currents of French and American strategic thought since 1945. In 1988, he entered the Fondation pour les etudes de defense nationale, where until 1992 he was student and assistant to General Lucien Poirier, a theoretician in nuclear deterrence. During several stays in the United States, he trained in the physics of nuclear weapons and in ballistics from the perspective of oversight processes for arms control treaties.