His family moved to Palestine where he became an early member of the Communist Party of Palestine's youth organization in 1922 but was later expelled because he disagreed with the positions of the Communist International on the national question, which supported the Arab national movements.

[1] 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.

During the war and the German occupation of France, the ICL’s International Bureau led by Vercesi considered that there was no purpose in the fractions’ continuing their work.

He joined the Fraction Française de la Gauche Communiste Internationale which had been formed in 1943 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 individuals and formed Gauche Communiste de France.