In simple terms, power means ability to rule. It is the ability to change or affect the behaviour or actions of another in the way one likes. For example, power is the ability of Mr A to compel Mr B to do something, which Mr B would ordinarily not want to do. Thus, in defining power, the word 'ability' is very important.
The Argentine military dictatorship, also called the National Reorganization Process, was a civic-military dictatorship that occurred in Argentina between 1976 and 1983.
This happened after the military coup that overthrew the government of MarΓa Estela MartΓnez de PerΓ³n, immediately installing a military junta that had Jorge Videla as de-facto president.