This chapter explores how different proponents of the idea of a competition–democracy nexus envisaged the opertationalisation of the twin-goal of republican liberty and democracy through the protection of competitive markets as an institution of antipower. Various republican antitrust paradigms shared the idea that competitive markets operate as an institution of antipower that maximises liberty as non-domination and promotes republican democracy as long as they diffuse economic power polycentrically amongst a multitude of independent economic agents. Based on this assumption, all iterations of the competition–democracy nexus saw the role of legal rules and, most notably, competition law as securing a polycentric and deconcentrated market structure. The various republican antitrust paradigms also envisaged different ways through which competition law can guarantee and preserve polycentric competitive markets. These design approaches can be largely divided into two categories: situational and conduct-based structuralism.