In their article Imperfect Alternatives: Institutional Choice and Reform of Investment Law, Sergio Puig and Gregory Shaffer develop a clear and discerning comparative framework to evaluate alternatives to the current system of investor-state dispute settlement (ISDS). In her essay Incremental, Systemic, and Paradigmatic Reform of Investor-State Arbitration, Anthea Roberts offers us a bracingly candid typology to describe the various actors involved in the recent efforts toward reform. My essay is meant to complement these excellent contributions and to focus unflinchingly on the tripartite role of the state itself. What I call the ISDS Trinity can be understood as shorthand for the state's systemic role as (1) law-giver, (2) protector of investment, and (3) respondent. Looking at current and future design trade-offs, I suggest that whether an institutional choice is embraced within the ISDS system has a lot to do with how well the reform validates each of these three roles. In this way, the ISDS Trinity offers further insight into how each state will approach the various trade-offs and intercamp dynamics described by Puig and Shaffer, and by Roberts, within the current debate. Put another way, the ISDS Trinity sheds additional light on whether a reform to the system will be well-received by a state and thus enjoy a greater chance of adoption.