However that Constitution was short-lived , as in 1937 , amidst growing Expansion extremism on the left Departing and right wings of the political spectrum , Vargas closed Process_end the National Congress and enacted Creating another Constitution , which established Building an authoritarian regime called Name_conferral Estado Novo .

The Portuguese conservative and authoritarian regime at the time , `` Estado Novo '' , was overthrown Change_of_leadership by a military coup in 1974 , and the change in government brought Bringing the conflict to an end .

Unlike other European nations during the 1950s and 1960s , the Portuguese Estado Novo regime did not withdraw Escaping from its African colonies , or the overseas provinces ( `` províncias ultramarinas '' ) as those territories had been officially called Name_conferral since 1951 .

By 1973 , the war had become Becoming increasingly unpopular due to its length and financial costs , the worsening of diplomatic relations with other United Nations members , and the role it had always played Participation as a factor of perpetuation of the entrenched Estado Novo regime and the non-democratic status quo .

The 28 May 1926 `` coup d'état '' , sometimes called 28 May Revolution or , during the period of the authoritarian Estado Novo ( ) , the National Revolution ( ) , was a military coup Change_of_leadership of a nationalist origin , that put an end to Process_end the unstable Portuguese First Republic and initiated Process_start 48 years of authoritarian rule in Portugal .