The main objective of this thesis is to investigate, using the dialectical method, why human rights are not only just emancipatory in the international context but are also often used for the legitimation of repressive policies. The argument in this thesis accepts that human rights have an important role in the general development of international law, and that their historical development has had a transformational effect on international politics. My thesis is that political groups have sought to mould political and social interactions by questioning and reshaping both the definitions and the system of human rights. In doing so, those actions – defined as political power – are used to legitimise new social and political constellations by changing the legal definitions of rights and by erecting new forms of protection. In the development of my argument, I analyse first the different historical moments in which significant transformations and redefinitions of human rights occurred. For that, I will identify two processes: the formalisation of rights (emancipatory) and their de-formalisation (repressive). Secondly, I will seek to show that these processes are politically constituted in a dialectic that operates in the implementation of such rights by the State in both domestic and international spheres. I shall then provide an interpretation that tries to explain how this dialectic has helped legitimise the system of international human rights. As a result, it can be observed that while in the West there was, domestically, an emancipatory movement able to formalise rights that progressively reached larger social groups, the same cannot be said for those who lived in the colonial world. Internationally, there have been different interpretations that prevented the expansion and implementation of human rights on the same basis as in the domestic sphere. The dialectic of emancipation and repression, therefore, can be visualised by looking, historically, at political struggles between formalising and de-formalising forces.