It was a military coup inside a military coup inside a military coup.

The original coup that instated the regime was a revolt led by high officials in the wake of a scandalous counterfeit money scheme. The post WWI military felt their wages shrink in purchasing power and pointed fingers at the very unstable and young republican goverment.

Hence the coup and following fifty years of fascism that by all measures was instated against the military plans. They wanted a military-run country. They apointed a general for president. He appointed a strongman for running the daily affairs. The civilians still got back the true governing and the military were pushed aside.

Come 1974, it was a rebellion of low ranking officers that threw the regime, with a good dose of communist (read popular) insatisfaction into the mix.

To quote the head officer:

"Meus senhores, como todos sabem, há diversas modalidades de Estado. Os estados socialistas, os estados capitalistas e o estado a que chegámos. Ora, nesta noite solene, vamos acabar com o estado a que chegámos!”

Running a state is a job for civilians. Making sure those civilians toe the line is the military to enforce, after the population set it. In 2013 we had the military remembering the then government remembering it was their sworn duty to uphold and defend the Constitution, which was constantly being ignored by several attempts of law.