This chapter analyses two alternative explanations of the alliances of Syria. The two explanations are based on structural realism and on constructivism. A brief study of two different paradigms will complement and frame the model of this analysis. These two paradigms have been chosen because they share important features with the theoretical approach of the book. Systemic analysis and particularly ‘balancing against’ dynamics are key factors shaping alliances in the model of this research. This book also integrates a domestic factor, defined as ideological orientation. The role of ideology in shaping foreign policy has been a classical feature of constructivist work, and particularly of the constructivist branch of authors such as Michael Barnett.