Portugal's redemocratization process started with the Carnation Revolution of 1974. It ended with the enactment of the Constitution of Portugal in 1976. Background: the Salazar-Caetano era The 28 May 1926 coup d'état replaced the republic with a military dictatorship that promised order, authority, and discipline. The military regime abolished political parties, took steps against the small but vocal Marxist groups, and did away with republican institutions. In 1928 it invited University of Coimbra professor António de Oliveira Salazar to serve as minister of finance. In 1932 he became Prime Minister. That year marked the beginning of his regime, the New State (Estado Novo). Under Salazar (1932–68), Portugal became, at least formally, a corporative state. The new Constitution of 1933 embodied the corporatist theory, under which government was to be formed of economic entities organized according to their function, rather than by individual representation. Employers were to form one group, labor another, and they and other groups were to deal with one another through their representative organizations. In reality, however, Salazar headed an autocratic dictatorship with the help of an efficient secret police – the PIDE. Strict censorship was introduced, the politically suspect were monitored, and the regime's opponents were jailed, sent into exile, and occasionally killed. Portugal drifted and floundered under this repressive regime for several decades. Economic conditions improved slightly in the 1950s, when Salazar instituted the first of two five-year economic plans. These plans stimulated some growth, and living standards began to rise. 1960s and the Colonial War The 1960s, however, were crisis years for Portugal. Guerrilla movements emerged in the Portuguese African overseas territories of Angola, Mozambique and Guinea that aimed at liberating those territories from "the last colonial empire". Fighting three guerrilla movements for more than a decade proved to be enormously draining for a small, poor country in terms of labour and financial resources. In the early 1960s the rise of new technocrats with a background in economics and technical-industrial expertise led to a new period of economic fostering, with Portugal as an attractive country for international investment. Industrial development and economic growth would continue throughout the 1960s. During Salazar's tenure, Portugal participated in the founding of the European Free Trade Association (EFTA) in 1960 and the Organisation for Economic Co-operation and Development (OECD) in 1961. In the early 1960s, Portugal also added its membership in the General Agreement on Tariffs and Trade (GATT), the