[1] During the 1905 Kishinev Pogrom Tze'irei Zion issued a circular in which it called on the Jewish youth to organize self-defense units.
The delegates who were present decided to cooperate with Bolshevik Russia and established the Zionist Socialist Party [he] (1920–1926).
It operated legally in the Soviet Union, until the clamp-down and emigration of nearly all members to Palestine and joined Ahdut HaAvoda.
Another part joined the Hapoel Hatzair Zionist group and operated illegally in the Soviet Union.
[3] A similar left-right split happened in 1923 among the members of the movement which stayed in Poland after the Russian Revolution.