*This article analyses the evolving relations between the military and political power in Portugal, from the time of the 19 th century liberal monarchy until the end of the 20 th century. In particular, it offers an interpretation of the impact of the diffusion of constitutionalist, republican, nationalist and socialist ideologies on military culture, and the norms guiding the attitudes and actions of military elites within the political arena. It takes into account their professional experience of war (the African campaigns, the First World War and the colonial war of 1961-74) and the observed behaviour of the working classes recruited for these missions, in the context of the policies adopted by successive governments and political regimes. The international context is also considered, both with regard to dominant ideologies and established strategic interests.