The military-led coup can be described as the necessary means of bringing back democracy to Portugal, ending the unpopular Colonial War where thousands of Portuguese soldiers had been commissioned into military service, and replacing the authoritarian Estado Novo (New State) dictatorship and its secret police which repressed civil liberties and human rights.

What motivated the "captains" was, essentially, a desire for back wages and the freedom until then denied to the Portuguese people and the dissatisfaction with the policies followed by the government in relation to the Colonial War and military law.

His appeals to the maioria silenciosa ("silent majority"), to resist the political radicalization of the left after the failed coup of 28 September 1974, and his tentative involvement in the rightist counter-revolution on 11 March 1975 (wherein he fled to Brazil)[7] were clear examples that Spínola had changed his allegiances.

As the author Günter Wallraff wrote in his book Aufdeckung einer Verschwörung – die Spínola-Aktion, Spínola was always interested in returning to power and eliminating his political adversaries.

Spínola's group was the MDLP – Movimento Democrático de Libertação de Portugal ("Democratic Movement for the Liberation of Portugal") an anti-communist network of terrorist bombers, responsible for the death of a priest, and whose operatives included Carlos Paixão, Alfredo Vitorino, Valter dos Santos and Alcides Pereira.

As the pro-communist inspiration of the Junta was becoming increasingly evident, and far-left factions were taking the leading edge of the revolution, the process was halted by the failed coup of 25 November 1975.

The moderates eventually won and this prevented post-revolutionary Portugal from becoming a left or right wing-ruled regime, being governed by centrist leaders.