He emigrated to France, where he joined the French Communist Party before being expelled at the same time as the members of the Left Opposition. He became a member first of the (Trotskyist) Ligue Communiste and then of Union Communiste, which he left in 1938 to join the Italian Fraction of the International Communist Left (ICL), since he agreed with the latter'sposition on the Spanish civil war against that of Union Communiste. During the w a r and the German occupation of France, the ICI's International Bureau led by Vercesi considered that there was nopurpose in the frac- tions' continuing their work. He however pushed for the reconstitution of the Italian Fraction around a small nucleus in Marseille. He joined the Fraction française de la gauche communist internationale which had been formed in 1944 and was close to Amadeo Bordiga. However, he split with the Bordigist tendency in May 1945, when he opposed the decision of the Italian Fraction's conference to dissolve the fraction, its militants joining the recently formed Partito Comunista Internazionalista as indi- viduals and formed Gauche Communist de France. After Gauche Communist de France dissolved in 1952 he left France for Venezuela in anticipation of World War III. He stayed there until 1968, developing a small current of revolutionaries in a group called Internationalism (Venezuela), then returned to France, where he and some of his Venezuelan recruits launched Revolution Internationale (RI).