Althusser was a lifelong member of the French Communist Party. Sometimes he criticised the party strongly. His arguments and theses were set against the threats that he saw attacking the theoretical foundations of Marxism. These included both the influence of empiricism on Marxist theory, and humanist and reformist socialist orientations which could be seen as divisions in the European Communist Parties, as well as the problem of the 'cult of personality' and of ideology itself. 