Coopting a rival faction leader into leadership prevented a cross-faction alliance
Evidence
Battle lines had been drawn publicly, and at the Fifth Congress the Russian majority leaders were above all preoccupied with preventing the opposition from winning international allies. The obvious candidate to lead an international fraction in support of the Russian opposition was Bordiga—in spite of the fact that Trotsky had led the attack on the latter’s rejection of the united front at the Fourth Congress and on his espousal of the “theory of the offensive” at the Third. For there was an obvious convergence between Bordiga’s views on the degeneration of the Comintern and Trotsky’s on the degeneration inside the Bolshevik party. Zinoviev sought to prevent such an alliance by incorporating Bordiga into the Comintern leadership with the post of vice-president. He saw a bloc between the Centre and the Left as the best solution to the P.C.I.’s internal divisions, and as a consequence of the tactical shift to the left which he had made after the German defeat no longer viewed Tasca and the Right with the same favour. — Antonio Gramsci, Selections from the Prison Notebooks, 176