Haim Kantorovitch

Haim Kantorovich was the second Secretary-General of the UASR, following his predecessor's retirement from politics in 1937. An Ashkenazi Jewish immigrant from the former Russian Empire, Kantorovich was a prominent member of Yiddish-speaking sections of the Socialist Labor Party, and an organizer among women's garment workers in New York City.

After a stint in prison for war resistance work against the Great War, Kantorovich would rejoin the Workers' Communist Party. An enthusiastic believer in revolutionary socialism, he nonetheless maintained a critical stance to the Bolshevik Revolution, and would rise in prominence during the party's Civil War reconstruction.