By all accounts, the constitutional and antitrust state-action doctrines are strangers. Courts and scholars see the constitutional state-action doctrine as about the applicability of constitutional rights in private disputes, and the antitrust state-action doctrine as a judicial negotiation between the scope of the Sherman Act and the demands of federalism. In this conventional view, the only thing the doctrines share in common is that they are both an awful mess. This Article challenges the conventional wisdom and argues that the two state-action doctrines are fundamentally connected, and when viewed in a certain light, really not even all that messy. It’s not that the traditional readings of the two doctrines have been wrong, so much as they persistently fail to take notice of the political theory that threads the two doctrines together. That theory is liberal legalism, and in the context of liberalism the two state-action doctrines bear witness to a story about American "competition law" that is only half-told in the conventional fields of law and economics. To better understand the legal foundations of market society, as well as the requisites of market reform, we need something other than an "economic analysis of law," much less a singular focus on various forms of economic regulation. What is needed instead is an image of the structure of market society, and an understanding of the deep premises that make that image possible. In the service of that goal this Article maps the manner in which these underground notions inform the background rules of the market through the use of the constitutional state-action doctrine, and simultaneously manage the market through the use of regulatory devices like antitrust law. These are the premises of our liberal legalism, and a fruitful field of their study lies in the surprising connection between the two state-action doctrines.