Born Mar. 11, 1877; died May 7, 1941. Activist in the Dutch workers’ movement.
In 1898, Wijnkoop became a member of the Social Demo- cratic Workers Party of the Netherlands, but he was ex- pelled in 1909 with a group of left social democrats that founded the Social Democratic Party of the Netherlands that year. During World War I, Wijnkoop was an internationalist and collaborated in the journal Vorbote. In 1918 he partici- pated in the founding of the Communist Party of the Nether- lands (CPN) and was elected its chairman. In 1925 he spoke against the policies of the CPN and the Comintern from a position of ultraleft sectarianism, and for this he was ex- pelled from the party the following year. In 1930 the party accepted him again, and from 1935 he was a member of the Central Committee of the CPN.