Background
After independence in 1962 he headed a powerful military faction within the government, and was made defence minister with the support of the Algerian leader Ahmed Ben Bella, whose ascent to power he had assisted as chief of staff. He grew increasingly distrustful of Ben Bella's erratic style of government and ideological puritanism, and in June 1965, Boumédienne seized power in a bloodless coup. The country's constitution and political institutions were abolished, and he ruled through a Revolutionary Council of his own (mostly military) supporters. These were mainly drawn from his companions during the war years, when he was based around the Moroccan border town of Oujda, which caused analysts to speak of the "Oujda group". (One prominent member of this circle was Boumédienne's long-time foreign minister, Abdelaziz Bouteflika, who is since 1999 Algeria's president.)
Initially lacking a personal power base, he was seen as potentially a weak ruler, but after a botched coup attempt against him by military officers in 1967 he tightened his rule. He then remained Algeria's undisputed ruler until his death in 1978, as all potential rivals emerging from within the regime were purged or relegated to symbolic posts; among them several members of the former Oujda group.

After independence
Economically, Boumédienne turned away from Ben Bella's focus on rural Algeria and experiments in socialist cooperative businesses (l'autogéstion). Instead, he opted for a more systematic and planified programme of state-driven industrialization. Algeria had virtually no advanced production at the time, but in 1971 Boumédienne nationalized the Algerian oil industry, increasing government revenue tremendously (and sparking intense protest from the French government). He then put the soaring oil and gas resources -- enhanced by the oil price shock of 1973 -- into building heavy industry, hoping to make his country the Maghreb's industrial centre. His years in power were in fact marked by a reliable and consistent economic growth, but after his death in the 1980s, the drop in oil prices and increasingly evident inefficiency of the country's state-run industries, promted a change in policy towards gradual economical liberalization.
In the 1970s, along with the expansion of state industry and oil nationalization, Boumédienne declared a series of socialist revolutions, and strengthened the leftist aspect of his regime. This allowed for a rapprochement with the hitherto suppressed remnants of the Algerian Communist Party (the PAGS), whose members were now co-opted into the regime, although without formal legalization of their party. Algeria formally remained a single-party state under the FLN, but Boumédienne's personal rule had marginalized the ex-liberation movement, and little attention was paid to the affairs of the FLN in everyday affairs. From the mid-1970s, constitutional rule was gradually reinstated and political institutions reestablished. Political pluralism was not tolerated in Boumédienne's Algeria, even if a brief moment of somewhat more relaxed public debate was allowed preceeding the adoption of a constitution that reestablished political institutions, in 1976. However, the referendum typically ended in virtually unanimous approval of the government-backed document. With the recreation of the office of President following this, Boumédienne was himself elected in a single-candidate election.

Foreign policy
In 1978, his appearances became increasingly rare. After lingering in a coma for 39 days, he died of a rare blood disease, Waldenström macroglobulinemia, following unsuccessful treatment in Moscow. Rumors about his being assassinated or poisoned have surfaced occasionally in Algerian politics, perhaps due to the rarity of the disease. The death of Boumédienne left a power vacuum in Algeria which could not easily be filled; a series of military conclaves eventually agreed to sidestep the competing left- and rightwing contenders, and designate the highest-ranking military officer, Col. Chadli Bendjedid, as a compromise selection.[1] Still, factional intrigue mushroomed after Boumédienne's death, and no Algerian president has since gained the same complete control over the country as he had.