Marxists have had a complex and contentious relationship to the question of both cosmopolitanism and antisemitism. The difficulties and problems they have encountered with each may, however, be related. They can be traced back to a repeated failure to take seriously Marx’s initial critique of contemporary antisemites and his simultaneous adoption of a cosmopolitan approach to politics which set him apart from many of his peers. Rather than confronting antisemitism, many Marxists adopted the view that it contained some kind of rational kernel, whilst drifting towards an accommodation with forms of nationalism. Having ignored and largely failed to respond to the mortal threat that a radicalized antisemitism posed for Jews, the self-proclaimed Marxists ruling the Soviet Union then accused Jews of being both nationalists (of the wrong, Zionist sort) and cosmopolitans (now a term of abuse). There is, however, an alternative tradition that may be recovered, albeit on the margins of the Marxist movement, in the later work especially of Horkheimer and Adorno, and in some parallel way also of Hannah Arendt, that sees antisemitism from a cosmopolitan perspective as an inherently reactionary political force which (as it became genocidal) came to threaten both Jews and humanity at large. [ABSTRACT FROM PUBLISHER]