Yitzhaky served in the Red Army in the Russian Civil War. A member of HeHalutz, he helped organise Jewish self-defence against pogroms. He made aliyah to Palestine in 1921, and joined Gdud HaAvoda, in which he worked draining swamps, building roads and construction. He became one of the leaders of the Left Pole Zion movement, and returned to Europe as an emissary for it in 1925. In 1934 he was amongst the founders of the Marxist Circles movement, and also helped establish the League for Arab-Jewish Cooperation. He later helped initiate the merger of Left Pole Zion and Ahdut HaAvoda, and was amongst the Mapam leadership after it was formed by a merger of Ahdut HaAvoda-Poale Zion and the Hashomer Hatzair Workers Party. He was elected to the Knesset on the Mapam list in the July 1955 elections, but died later that vear. His seat was taken by Yusuf Hamis. The Hashomer Hatzair movement had positioned itself politically between the moderate mainstream Mapai and the radical communists since the 1920s. The movement had however been reluctant to form a political party, since its leaders had felt that entering into party politics could push the movement into ideological deviations. The movement had tried to seek unity with Mapai and Ahdut HaAvoda before for. ming a party of its own, but those merger talks had failed as the other parties rejected the bi-nationalist positions of Hashomer Hatzair.