Complex sentence: A Marxist, he helped found the Social Democratic Party of Canada and was an opponent of conscription during the Conscription crisis of 1917 and was an organiser of the Winnipeg General Strike in 1919.
Split into simpler sentences: A Marxist, he helped found the Social Democratic Party of Canada and was an opponent of conscription during the Conscription crisis of 1917. He was also an organiser of the Winnipeg General Strike in 1919.