Regional Internet Address Registries (RIRs) are private, nonprofit and transnational governance entities that evolved organically with the growth of the Internet to manage and coordinate Internet Protocol addresses. The RIR's management of Internet address resources is becoming more contentious and more central to global debates over Internet governance. This is happening because of two transformational problems: 1) the depletion of the IPv4 address space; and 2) the attempt to introduce more security into the Internet routing system. We call these problems "transformational" because they raise the stakes of the RIR's policy decisions, make RIR processes more formal and institutionalized, and have the potential to create new, more centralized control mechanisms over Internet service providers and users. A danger in this transition is that the higher stakes and centralized control mechanisms become magnets for political contention, just as ICANN's control of the DNS root did. In order to avoid a repeat of the problems of ICANN, we need to think carefully about the relationship between RIRs, governments, and Internet freedom. In particular, we need to shield RIRs from interference by national governments, and strengthen and institutionalize their status as neutral technical coordinators with limited influence over other areas of Internet governance.