In general, the decision by foreign governments to get involved in the Spanish Civil war was a result of both ideology and self-interest.
Foreign intervention had two main effects. The first was that it both intensified and lengthened the war, and the other is that it meant that the Spanish issues that caused the war were overtaken and submerged by the wider ideological battles taking place in Europe. Both sides realized the importance of foreign aid and support. Propaganda played a key role in this. The Nationalists argued that they represented the cause of Christianity, order and Western civilization against Communism. The Republicans argued that they were the legally elected government of Spain which was under attack from anti-democratic generals and fascist dictatorships.
-Britain and France remained neutral and pursued a non-intervention policy. The United States also adopted the non-intervention policy influenced by the powerful Catholic. This prevented the Republic from purchasing arms openly and hampered its ability to resist the Nationalist threat.
-Britain took the lead in establishing the NIC(Non-Intervention Committee) in September 1936. Britain’s fear was that the war would spread and become a general European conflict. However, three of the key members of the NIC- Germany, Italy and USSR ignored the NIC completely and became the main forces in Spain. In addition, Britain’s non-intervention policies were limited and tended to favor the Nationalists. They focused on preventing aid