Angus joined the New Democratic Party (NDP) in 1962 and then the Young Socialists in Ottawa in 1964. Angus participated in the formation of the Canadian Trostkyist party Revolutionary Workers League (fusion of the Local Search Association with the Revolutionary Marxist Group and Groupe Marxiste Revolutionaire) in 1977. He left the RWL in 1980.
He was active in the YS and the League for Socialist Action into the 1970s. Angus is the founder and director of Socialist History Project and was an editor of Socialist Voice. Angus is an advisory editor of Socialist Resistance.
He was a founding member and Coordinating Committee Member of Ecosocialist International Network and is a member of Canadian Dimension editorial collective.
