The article focuses on the theory of humanitarian intervention and its applicability to actual meddling in the affairs of other states including military operations - directly or indirectly - sanctioned by the UN. The authors begin with the assumption that intervention and war are not dissimilar because war might be regarded as a radical form of intervention. Historical condition and normative justifi cation of the emergence of the legality and legitimacy of war are reconstructed with the view to highlight the antinomy between defending the state sovereignty and defending the human rights. We opt for the contractarian approach, which, in our view, allows us to overcome the antinomy, and we argue that in international law it is the violation of the human rights by the state that should be the universal and paramount legitimation for intervention. Further analysis of political practices, however, reveals that human rights are rarely invoked in legitimizing intervention. Yet, we demonstrate that classical political realism that prioritizes interests of the state is itself in need of justifi cation if it is used for legitimizing intervention, because its main tenet is the supremacy of the state, which is undermined by intervention. In conclusion, we highlight the methodological problems in normative political theory, which faces the choice of what is to be the “foundational notion” for modern international law.