The feud had simmered since the late 1930s over ideological differences, particularly the questions of the Moscow Trials and of Hellman's support for the "Popular Front" with Stalin.
A disputa acendeuse desde finais da década dos 30 sobre as súas diferenzas ideolóxicas, particularmente as cuestións dos xuízos de Moscova e do apoio de Hellman á "Fronte Popular" e a Stalin.