With the outbreak of World War II, Abbas volunteered to rejoin the medical corps of the French Army. After his service, his political views continued to evolve and he turned away from France after General Giraud refused his requests to allow Muslims to enlist in their fight against the occupying forces as equals. His desire for change continued and he turned to nationalism, issuing the "Manifesto of the Algerian People" on Feb. 10, 1943. The manifesto made apparent the philosophical changes that Abbas had undergone. He now condemned colonial rule by the French and demanded Algerian self-determination. Abbas argued the need for an Algerian constitution, which would grant equality to all Algerians. In May he, along with some colleagues, added a clause foreseeing a sovereign Algeria. The manifesto was published on June 26, but was rejected by the governor general. He, along with Messali Hadj form the Amis du Manifeste et de la Liberté, and called for an autonomous republic. This initiative resulted in Abbas being imprisoned for a year, and the quick dissolution of the AML. In 1946, Abbas formed the nationalist political party Union Démocratique du Manifeste Algérien (UDMA) when he was elected member of the Constituent Assembly of France. This new organization called for a more moderate approach, such as the formation of an Algerian state with the full cooperation of the French. 1946 also saw him named as editor of the publication "Egalité". He remained active in politics as a member of the Algerian Assembly through 1955. During these years he was arrested twice by the French. His continuing efforts as a moderate nationalist did not succeed and he fled to Cairo, in 1956. While in Cairo, he worked alongside Ahmed Ben Bella, a fellow revolutionary.