An active Zionist , he was elected to the Executive of the WZO .
An active Zionist , he was worked closely with Chaim Weizmann in their efforts to define and lead the WZO during the 1920s and 1930s , and contributed to early drafts of the Balfour Declaration .
An active Zionist , he was elected to the Executive of the WZO , and worked closely with Chaim Weizmann in their efforts to define and lead the WZO during the 1920s and 1930s , and contributed to early drafts of the Balfour Declaration .