This chapter examines the social, political, and economic factors underlying the Salvadoran civil war, and the development of the organizations that ultimately contested the war. The military government's intense, disproportionate repression of even moderate reformers both accelerated progress toward war and served as a tactic of war. Similarly, the histories, and prehistories, of both state and rebel organizations informed their strategies and tactics in conflict. El Salvador's civil war featured well-organized, ideologically sophisticated Communist rebels, who sought control of the state, rather than resource wealth, secession, or ethnic domination. Facing them was a generally inept and brutal state force, which ultimately required vast amounts of assistance from the United States—military and otherwise—to avoid losing the war outright. Yet there was little demographic difference between the fighting forces, in terms of age, education, ethnicity, or other factors. The chapter then looks at some broad, structural similarities and differences between El Salvador's war and others.