Hapoel Hatzair
The year after immigrating, Bader became a member of the Haganah planning committee. A member of the Histadrut trade union, and later its Actions Committee, he was amongst the founders of the gar'in which established kibbutz Mizra. He was also a member of Hapoel Hatzair and HaMerkaz HaHakla'i, and in 1930 joined Hashomer Hatzair.