In the late 1960s, the CPA, under the leadership of National Secretary Laurie Aarons, became a strong supporter of "Eurocommunism", of abandoning Leninism and democratic centralism, and trying to form a "united front" of the various left-wing forces thrown up by the movement of opposition to the Vietnam War. The CPA leadership had become increasingly critical of the Soviet Union, particularly over the 1968 Warsaw Pact invasion of Czechoslovakia. Dissidents took the view that the CPA should not become a left social-democratic party, and should continue as a Marxist–Leninist party. The group was described as pro-Soviet hardliners. Their position put them at odds with the CPA leadership.