Sorry for the double posting mods, but I wanted to add some interesting info that I forgot.
I will give you a few "jewels" of the leader of the PSOE:
In 1925 Francisco Largo Caballero became leader of the PSOE. He called for "the conquest of political power by the working class by whatever means possible" and the "dictatorship of the proletariat organized as a working-class democracy".
Francisco Largo Caballero, speech in Madrid (March 1936)
The illusion that the proletarian socialist revolution can be achieved by reforming the existing state must be eliminated. There is no course but to destroy its roots. Imperceptibly, the dictatorship of the proletariat or workers' democracy will be converted into a full democracy(

), without classes from which the coercive state will gradually disappear. The instrument of the dictatorship will be the Socialist party, which will exercise this dictatorship during the period of transition from one society to another and as long as the surrounding capitalist states make a strong proletarian state necessary.
Edward Knoblaugh, Correspondent in Spain (1937)
Largo Caballero began to realize the need for immediate drastic action. As president of the U.G.T., he summoned the sub-leaders of this Revolutionary Socialist group and impressed upon them the desperateness of the situation. The result was a round-table conference among the U.G.T., the heads of the Syndicalists National Confederation of Labor (C.N.T.), The Federation of Iberian Anarchists (F.A.I.), The Trotsky Communists (Partido Obrero Unificado Marxists - P.O.U.M.), The Stalin Communists and the Left Republicans. In the first agreement which these divergent factions had been able to reach since the beginning of the war they approved the immediate mobilization of all able-bodied men in Loyalist territory. A decree to this effect was issued. Whether they wanted to join or not, all men between the ages of 20 and 45 were pressed into military service. From this moment on, the Loyalist army ceased to be a voluntary army.
Check this:
Joseph Stalin became concerned that the Nationalists would defeat the Republicans in Spain. He took the view that four extreme right-wing governments in Europe would pose a serious threat to the security of the Soviet Union. Although Stalin continued to support the idea of the Nonintervention Agreement, he was now willing to supply the necessary military aid to stop a fascist regime being established in Spain.
Stalin encouraged the Comintern to organise the formation of International Brigades. He also sent Alexander Orlov of the NKVD to advise the Popular Front government. Orlov supervised a large-scale guerrilla operation behind Nationalist lines. He later claimed that around 14,000 people had been trained for this work by 1938.
The Soviet Union provided considerable help to the Spanish Communist Party to improve its position in the Popular Front government. This included the removal of the socialist Francisco Largo Caballero as prime minister and replacing him with the communist sympathizer, Juan Negrin.
Alexander Orlov also used NKVD agents to deal with left-wing opponents of the Communists in Republican held areas. This included the arrest and execution of leaders of the Worker's Party (POUM), National Confederation of Trabajo (CNT) and the Federación Anarquista Ibérica (FAI).
The Soviet Union were the main suppliers of military aid to the Republican Army. This included 1,000 aircraft, 900 tanks, 1,500 artillery pieces, 300 armoured cars, 15,000 machine-guns, 30,000 automatic firearms, 30,000 mortars, 500,000 riles and 30,000 tons of ammunition
Again, thanks god that the comunist didn´t win. Remeber that Stalin is the biggest murderer ever, he killed 40 million russians in his famous
Gulag I can imagina what would have happen if they won the war.