The Spanish Civil War was Anarchists, Communists, and Liberals vs. a Hitler and Mussolini backed fascist Dictator, Franco.
It was Anarchists vs Communists vs Liberals, some of whom aligned with a fascist military commander because they didn't like how the Anarchists and Communists were treating the Catholic Priesthood.
The resistance had popular support, but the lack of weapons did severely hinder the left’s effectiveness
The Communists were running the country by the 30s. They had all the weapons they could have desired. What they lacked was a petite bourgeois willing to accept their socialist economic reforms. That friction split the military and resulted in a grisly civil war.
I’m not saying having a surplus of small arms in the hands of the leftists would’ve changed the outcome of the war
The anarchists, in particular, had sizable caches of small arms. It was the lack of tanks, airplanes, and artillery that seriously fucked them.
Incidentally, the Soviets were willing to support the Spanish Communists with some number of tanks, airplanes, and artillery. But accepting aid from Stalin meant pissing off the Anarchists (who would ultimately need those weapons when fighting the Fascists).
But the single biggest asset that the fascists enjoyed and the anarchists/communists lacked was trust in one another. Franco built his brand on the back of the Catholic Church in retreat and won the faith of the faithful. Manuel Azaña and Niceto Alcalá-Zamora lost the confidence of key supporters and were forced to watch the Second Republic disintegrate because the fractious caucuses of local independent groups couldn't align under a single national banner.
Also didn't hurt that Franco gleefully took favors from German, Italian, and American fascists, while the Spanish Anarchists and Communists were reluctant to accept more than token aid from friendly leftist groups abroad.
