Algeria's first president was the FLN leader Ahmed Ben Bella. Morocco's claim to portions of western Algeria led to the Sand War in 1963. Ben Bella was overthrown by his former ally and defense minister, Houari Boumédienne in 1965. Under Ben Bella, the government had already become increasingly socialist and authoritarian, and this trend continued throughout Boumédienne's government. However, Boumédienne relied much more heavily on the army, and reduced the sole legal party to a merely symbolic role. Agriculture was collectivised, and a massive industrialization drive launched. Oil extraction facilities were nationalized. This was especially beneficial to the leadership after the 1973 oil crisis. In the 1960s and 70s under President Houari Boumediene, Algeria pursued a programme of industrialisation within a state-controlled socialist economy. Boumediene’s successor, Chadli Bendjedid, introduced some liberal economic reforms and prosecuted a policy of Arabisation in Algerian society and public life. Teachers of Arabic, brought in from other Muslim countries, spread radical Islamic thought in schools and sowed the seeds of political Islamism.
The Algerian economy became increasingly dependent on oil, which led to hardship when the price collapsed during the 1980s oil glut. Economic recession caused by the crash in world oil prices resulting in social unrest during the 1980s and ultimately forced Bendjedid to bring in a multi-party system at the end of the decade. Political parties developed such as the Front Islamique du Salut (FIS), a broad coalition of Islamist groups.