Sure, I meant across decision makers. Realpolitik (the rest is propaganda).
Before and in the beginning of the Spanish Civil War, when the great Orwell fought, the left in Spain was extremely atomized: there were the anarchist (very active in the beginning), the socialists, the communists (actually a minority initially), and many splinter groups (like POUM). But, just like an equally varied right swiftly unified under Franco, so did the left, more slowly, under the "oficial" communist faction, which, although it decided to be mostly pragmatic until the war had been won, fought some of the other leftists as fiercely as it fought the right.
Yes, that was one factor for sure. But it was actually really complicated, quite mind boggling in fact. The thing is that, in spite of Stalin being pretty much the only effective external support the Spanish republic had, the communists inside Spain were pretty much a marginal group when the war started, and had to resort to all kinds of intrigues to get support from both the population and the, still, official government, and also to had get rid of rival groups, like the ones you mentioned.
Yeah - I read Homage to Catalonia again recently - I have read The Battle for Spain by Antony Beevor a while back but as you say, it is quite complex - I need to read it again!
Before and in the beginning of the Spanish Civil War, when the great Orwell fought, the left in Spain was extremely atomized: there were the anarchist (very active in the beginning), the socialists, the communists (actually a minority initially), and many splinter groups (like POUM). But, just like an equally varied right swiftly unified under Franco, so did the left, more slowly, under the "oficial" communist faction, which, although it decided to be mostly pragmatic until the war had been won, fought some of the other leftists as fiercely as it fought the right.