The 28th May 1926 coup d'état or, during the period of Estado Novo, the National Revolution (Revolução Nacional), was a military action that put an end to the chaotic Portuguese First Republic and initiated the Ditadura Nacional (National Dictatorship) (years later, renamed Estado Novo).
António de Oliveira Salazar developed the Estado Novo. The basis of his regime was a platform of stability. Salazar's early reforms benefited the whole nation since they allowed financial stability and therefore economic growth. After the chaotic years of the Portuguese First Republic (1910–1926) when not even public order was achieved, this looked like an impressive breakthrough to most of the population, Salazar achieved his height in popularity at this point. This transfiguration of Portugal was then known as "A Lição de Salazar" - Salazar's Lesson.
The Estado Novo enforced Nationalist and Catholic values on the Portuguese population. The whole education system was focused toward the exaltation of the Portuguese Nation and its 5 century old overseas territories (the Ultramar). The motto of the regime was Deus, Pátria e Familia (meaning God, Fatherland and Family). After 1945, the main raison d'être of the regime became resistance to the wave of decolonization which swept Europe after the end of World War II.
The Estado Novo accepted the idea of corporatism as an economic model. This policy was pursued in order to protect the elites and defend oligarchic capitalism as the economic system, under state paternalist supervision. Although Salazar refused to sign the Anti-Comintern Pact in 1938, the Portuguese Communist Party was intensely persecuted. So were Anarchists, Liberals, Republicans and anyone opposed to the regime. The only allowed party was the União Nacional (National Union), which encompassed a wide range of right-wing politics, passing through monarchism, corporatism, para-fascism, nationalism and capitalism.
The Legião Nacional was a Popular Militia similar to the Italian Blackshirts. For young people there was the Mocidade Portuguesa, an organization similar in organisation (but not in ideology) to the Hitler Youth. These two organizations were heavily supported by the State and imposed a martial style of life.
Some liberal economic reforms advocated by elements of the ruling party, which were successfully implemented under similar circumstances in neighbouring Spain, were rejected out of fear that industrialization would destabilize the regime and its ideological base and would strengthen the Communists and other left-wing movements. In 1962 the "Academic Crisis" occurred. The regime, fearing the growing popularity of democratic ideas among the students, carried out the boycott and closure of several student associations and organizations, including the important National Secretariat of Portuguese Students. The students, with strong support from the Portuguese Communist Party, responded with demonstrations which culminated on March 24 with a huge student demonstration in Lisbon that was brutally suppressed by the shock police, which led to hundreds of student injuries. Immediately thereafter, the students began a strike that marked a significant point in the resistance against the regime. The fear of many young men for the dangers of the Portuguese Colonial War resulted on hundreds of thousands of Portuguese workers each year to seek better economic and political conditions in more developed countries, or to escape conscription. In over 15 years nearly one million emigrated to France, another million to the USA, many hundreds of thousands to Germany, Switzerland, the UK, Luxembourg, Venezuela or Brazil. Political parties, such as the Socialist Party, persecuted at home, were established in exile. The only party which managed to continue (illegally) operating in Portugal during all the dictatorship was the Portuguese Communist Party.
The liberalization of the Portuguese economy gained a new impetus under Salazar's successor, Prime Minister Marcello José das Neves Caetano (1968-74), whose administration abolished industrial licensing requirements for firms in most sectors and in 1972 signed a free trade agreement with the newly enlarged European Community. Under the agreement, which took effect at the beginning of 1973, Portugal was given until 1980 to abolish its restrictions on most community goods and until 1985 on certain sensitive products amounting to some 10 percent of the EC's total exports to Portugal. Starting in 1960, EFTA membership and a growing foreign investor presence contributed to Portugal's industrial modernization and export diversification between 1960 and 1973. Caetano moved on to foster economic growth and some social improvements, such as the awarding of a monthly pension to rural workers who had never had the chance to pay social security. Some large scale investments were made at national level, such as the building of a major oil processing centre in Sines. Notwithstanding the concentration of the means of production in the hands of a small number of family-based financial-industrial groups, Portuguese business culture permitted a surprising upward mobility of university-educated individuals with middle-class backgrounds into professional management careers. Before the revolution, the largest, most technologically advanced (and most recently organized) firms offered the greatest opportunity for management careers based on merit rather than on accident of birth. On a long term analysis, after a long period of economic divergence before 1914, the Portuguese economy recovered slightly until 1950, entering thereafter on a path of strong economic convergence until the 1974 Carnation Revolution. Portuguese economic growth in the period 1950-1973 under the Estado Novo regime (and even with the effects of an expensive war effort in African territories against independence guerrilla groups), created an opportunity for real integration with the developed economies of Western Europe. Through emigration, trade, tourism and foreign investment, individuals and firms changed their patterns of production and consumption, bringing about a structural transformation. Simultaneously, the increasing complexity of a growing economy raised new technical and organizational challenges, stimulating the formation of modern professional and management teams.
The end of the Estado Novo began with the uprisings in the colonies in the 1960s. The Independence Movements in Angola, Mozambique and Guinea were supported by both the United States and the USSR, which both wanted to end all colonial empires and expand their own spheres of influence. The wars had the same effects in Portugal as the Vietnam War in the United States, or the Afghanistan War in the Soviet Union; they were unpopular and caused relatively high losses of troops for little gain, leading many to question the continuation of the war and, by extension, the government.
Although Portugal was able to maintain some superiority in the colonies by its use of elite paratroopers and special operations troops, the foreign support to the guerillas made them more manoeuvrable, allowing them to inflict heavy losses on the Portuguese army. The international community isolated Portugal due to the long Colonial War. The situation was aggravated by the death of Salazar, the strong man of the regime, in 1970. His replacement was one of his closest advisors, Marcelo Caetano, who tried to slowly democratize the country, but could not hide the obvious dictatorship that oppressed Portugal. In 1974, the Carnation Revolution in Lisbon, organized by left-wing military officers, overthrew the Estado Novo regime. By 1975, all African territories were independent.