Charles Lacheroy, a member of this group, was the first person to reflect on the reasons behind the 1954 French defeat at Dien Bien Phu, which all but put an end to the Indochina War (1946–54). Roger Trinquier, who theorised the systemic use of torture in counter-insurgency in "Modern Warfare: A French View of Counterinsurgency" (1961), was also a member of this organisation.