 Drafted into the French armed forces in 1939, Casanova was promptly taken prisoner; however, he escaped and resumed contact with the party through an intermediary, Claudine Chomat, in March 1942.Initially, he worked in the communist resistance with Pierre Villon, a period during which he met Pablo Picasso and Louis Aragon.He then served the National Military Committee of the FTP ("Francs-Tireurs et Partisans"), whose leader, Charles Tillon, proposed Casanova as the FTP's representative to the Provisional Consultative Assembly ("") of 1944 in Algiers, but he never attended.