There is no normative IR theory in Aron, only unavoidable normative implications of his sociological and theoretical approach of IR, because “normative implications are inherent in every [social sciences] theory”. The aim of this chapter is to structure these implications to reveal Aron’s international ethics in three oxymorons, i.e. appearances of contradiction : a liberal realism, an inspired ethic of responsibility, and a post-Kantian Machiavellianism.