The concept of a modern 'Jewish politics' is used to describe and explain the participation of the Jewish people in the political arenas of nineteenth- and twentieth-century European society. This chapter focuses on the role of the ethnicity in the 1945 election as well as reconsidering the nature of the Jewish sections and the question of what 'Jewish politics' is. It expresses that politicised ethnicity cannot by itself explain the-complex phenomenon of 'Jewish communism'. The chapter explores that Jewish left wing politics can only be understood through the intimate connections between political party, ethnic/non-ethnic identities and historical developments. To emphasise the paramount importance of the party, the actual structure of the Communist Party of Great Britain (CPGB) will act as the framework of interpretation in order to clearly reveal the subjects parameters and the interdependency of ethnicity and political structure. It outlines the three sections of CPGB: the party leadership, the district parties and the grass roots membership.