all groups—the armed forces, the opposition and liberals within the regime—that only a revolution could produce the changes that they felt Portugal sorely needed. Contributing to this feeling were a number of growing tensions on the political and social scene. Economic pressure The continuing economic drain caused by the military campaigns in Africa was exacerbated by the first great oil "shock" of 1973. Politically, the desire for democracy, or at least a greater opening up of the political system, was increasing. Social tensions mounted, as well, because of the slow pace of change and the absence of opportunities for advancement. The decisive ingredient in these tensions was dissension within the military itself, long a bulwark of the regime. Younger military academy graduates resented a program introduced by Caetano whereby militia officers who completed a brief training program and had served in the overseas territories' defensive campaigns, could be commissioned at the same rank as military academy graduates. Caetano's government had begun the program (which included several other reforms) in order to increase the number of officials employed against the African insurgencies, and at the same time cut down military costs to alleviate an already overburdened government budget. Spínola and revolution A key catalytic event in the process toward revolution was the publication, in 1973, of General António de Spínola's book, Portugal and the Future, which criticized the conduct of the war and offered a far-ranging program for Portugal's recovery. The general's work sent shock waves through the political establishment in Lisbon. As the first major and public challenge to the regime by a high-ranking figure from within the system, Spínola's experience in the African campaigns gave his opinions added weight. The book was widely seen as the opening salvo in Spínola's ambitious campaign to become president. 1974 uprising On 25 April 1974, a group of younger officers belonging to an underground organization, the Armed Forces Movement (Movimento das Forças Armadas – MFA), overthrew the Caetano regime, and Spínola emerged as at least the titular head of the new government. The uprising succeeded in hours with virtually no bloodshed. Caetano and other high-ranking officials of the old regime were arrested and exiled, many to Brazil. The military seized control of all important installations. Spínola regarded the military's action as a simple military uprising aimed at reorganizing the political structure with himself as the head, a "renovação" (renovation), in his words. Within