Jack MacDonald (nicknamed "Moscow Jack" Macdonald in the 1920s) born in Falkirk, Scotland, was a founding member of the Communist Party of Canada and one if its leaders. He was party Chairman from 1921 to 1923, and National Secretary from 1923 to 1929. MacDonald supported the expulsion of Maurice Spector for Trotskyism in 1928. Subsequently, he tried to play a balancing role between the Tim Buck's Stalinist faction and the party majority headed by Finnish, Ukrainian and Jewish groups of which J.B. Salsberg was a notable figture. Macdonald failed and was expelled from the party in 1931 being accused of being a Lovestoneite (that is a supporter of Bukharin's Right Opposition). MacDonald, however, maintained that he was attempting to play an independent role. Accusations of "Lovestoneism" are further undermined by the fact that MacDonald went on to reconcile with Spector and joined the Toronto branch of the International Left Opposition (Trotskyist) Canada in 1932. Falkirk is a town in Scotland, in the district of Falkirk. ... The Communist Party of Canada is a communist political party in Canada. ... Maurice Spector (1898 - August 1, 1968) was the Chairman of the Communist Party of Canada for much of the 1920s and an early follower of Leon Trotsky after his split from the Communist International. ... Trotskyism is the theory of Marxism as advocated by Leon Trotsky. ... Timothy (Tim) Buck (January 6, 1891-March 11, 1973) was a long-time leader of the Communist Party of Canada (known from the 1940s until the late 1950s as the Labour Progressive Party). ... Iosif (usually anglicized as Joseph) Vissarionovich Stalin (Russian: Иосиф Виссарионович Сталин), original name Ioseb Jughashvili (Georgian: იოსებ ჯუღაშვი&#4314... Joseph Baruch (J. B.) Salsberg (1903-1998) was a Canadian politician, long time Communist and activist in the Jewish community. ... Jay Lovestone (1897-1990) was at various times head of the Communist Party, leader of a small oppositionist party, and foreign policy advisor to the leadership of the AFL-CIO and various unions within it. ... Nikolai Ivanovich Bukharin ( Russian: Николай Иванович Бухарин), ( October 9 ( September 27 Old Style) 1888 – March 13, 1938) was a Bolshevik revolutionary and intellectual, and later a Soviet politician. ... The Right Opposition was the name given to the tendency made up of Nikolai Bukharin, Alexei Rykov and their supporters within the Soviet Union in the late 1920s. ... The International Left Opposition (Trotskyist) of Canada, the Workers Party of Canada, Socialist Policy Group, Socialist Workers League, Revolutionary Workers Party, League for Socialist Action and Revolutionary Workers League were names of successive Trotskyist organisations in Canada. ...

MacDonald and Spector sided with Martin Abern and Max Shachtman in a dispute within the Communist League of America that threatened to split the Trotskyist movement in North America in the early 1930s. The split emerged in the late 1930s, this time over the question of the class nature of the Soviet Union with both MacDonald and Spector siding with Shachtman in his split from the International in 1940. MacDonald subsequently dropped out of Marxist politics altogether. Martin Abern, born Martin Abramowitz (December 2, 1898 ? 1949) was a Trotskyist politician. ... Max Shachtman (September 10, 1904 - November 4, 1972) was an American Marxist theorist. ... The Communist League of America (Left Opposition) was founded by James P. Cannon, Max Shachtman and Martin Abern in 1928 after their expulsion from the Communist Party USA for Trotskyism. ...