Introduction : The Spanish Civil War (1936–1939) was not a sudden eruption of violence but the culmination of deep political and social tensions that had been developing in Spain for decades. Rooted in ideological polarization, class struggle, and institutional instability, the war reflected the failure of the Spanish Republic to reconcile conflicting visions of modernity and tradition. This essay argues that the main causes of the conflict lay in the collapse of political legitimacy, the radicalization of social movements, and the inability of moderate forces to sustain a democratic compromise. I. Political Polarization and Institutional Collapse The establishment of the Second Republic in 1931 marked the beginning of a period of reform and resistance. The Republic sought to modernize Spain through secularization, land redistribution, and military reform. However, these initiatives alienated powerful conservative institutions such as the Church and the Army. According to historian Paul Preston, the Republic’s progressive agenda “threatened the very foundations of traditional Spain,” fueling the emergence of reactionary forces determined to restore the old order. Meanwhile, the left fragmented between moderate Republicans and radical socialists, undermining the coherence of government. By 1936, political violence had become normalized, and both left and right viewed the use of force as a legitimate means to secure power. II. Social Tensions and Class Conflict Economic inequality and agrarian underdevelopment intensified class resentment, particularly in rural Andalusia and Extremadura. Large landowners resisted reform while landless peasants demanded redistribution. Historian Helen Graham notes that “social revolution was not an abstract idea but a daily necessity” for the rural poor. The polarization between employers and workers, landlords and peasants, was mirrored in urban centers, where anarchist unions such as the CNT gained mass support. Strikes, church burnings, and assassinations created an atmosphere of chaos that further eroded state authority. III. Ideological Radicalization and Foreign Influence Spain in the 1930s became a battleground of competing ideologies: fascism, communism, liberal democracy, and anarchism. The rise of Hitler and Mussolini emboldened Spanish conservatives, while the success of the Soviet Union inspired revolutionary optimism on the left. Historian Stanley Payne highlights how this ideological polarization turned political opponents into existential enemies. The 1936 electoral victory of the Popular Front was perceived by conservatives as a revolutionary coup, prompting the military uprising led by General Franco in July. International ideologies thus provided both the rhetoric and the justification for domestic conflict. Conclusion : The Spanish Civil War was the tragic outcome of political paralysis, social injustice, and ideological extremism. The Republic’s reforms, though ambitious, alienated traditional elites without satisfying popular demands. The breakdown of trust between left and right, coupled with external ideological pressures, made civil conflict inevitable. Ultimately, the war reflected Spain’s struggle to define its national identity between modernity and tradition — a struggle whose echoes would shape Spanish politics for decades. Suggested Sources : Preston, Paul. The Spanish Civil War: Reaction, Revolution, and Revenge. Graham, Helen. The Spanish Republic at War, 1936–1939. Payne, Stanley. The Spanish Civil War, the Soviet Union, and Communism.