The Left faction dominated the PCI apparatus despite refusing leadership posts
Evidence
Although it had only consultative status, the voting on these theses was a good index of the balance of strength in the P.C.I. at that moment. It showed that the Centre had a slender majority in the Central Committee over the Right, but that the Left—which had of course refused to participate in the leading bodies of the party— was overwhelmingly stronger than the other two factions combined in the party apparatus as a whole. — Antonio Gramsci, Selections from the Prison Notebooks, 162