From a young age, Curtin was active in both the Australian Labor Party and the Victorian Socialist Party, which was a Marxist organisation. While a member of the Victorian Socialist Party Curtin held strong anti-imperialist and anti-militarist views, and in opposition to the mainstream of the Labor movement, opposed racism due to his belief that racial hatred was used as a tool of the "exploiting class". Labor historian Graeme Osborne describes Curtin's stance as "anticipating Lenin in the view that imperialism was capitalism in its last stage".