Hapoel Hatzair
In 1930, Arlosoroff was influential in unifying the two major Zionist socialist political parties, the Poale Zion and the Hapoel Hatzair. This merger brought the establishment of the Mapai Labour Party. Through the Mapai's political muscle, Arlosoroff received election as a member of the Zionist Executive at the 1931 Zionist Congress. In addition, he was named Political Director of the Jewish Agency for Palestine, a prominent position he filled until his 1933 assassination.