In April 1937 the Irgun split after the referendum. Approximately 1,500–2,000 people, about half of the Irgun's membership, including the senior command staff, regional committee members, along with most of the Irgun's weapons, returned to the Haganah, which at that time was under the Jewish Agency's leadership. The Supervisory Committee's control over the Irgun ended, and Jabotinsky assumed command. In their opinion, the removal of the Haganah from the Jewish Agency's leadership to the national institutions necessitated their return. Furthermore, they no longer saw significant ideological differences between the movements. Those who remained in the Irgun were primarily young activists, mostly laypeople, who sided with the independent existence of the Irgun. In fact, most of those who remained were originally Betar people. Moshe Rosenberg estimated that approximately 1,800 members remained. In theory, the Irgun remained an organization not aligned with a political party, but in reality the supervisory committee was disbanded and the Irgun's continued ideological path was outlined according to Ze'ev Jabotinsky's school of thought and his decisions, until the movement eventually became Revisionist Zionism's military arm. One of the major changes in policy by Jabotinsky was the end of the policy of restraint.