"In this piece, we take up the case of the domain name system as an example of challenges and solutions for realspace sovereigns in cyberspace. First, we analyze the 'in rem' provision of the US Anticybersquatting Consumer Protection Act (ACPA), which purports to expand the scope of the ACPA to encompass disputes with little direct connection with the United States. In reality, there exist no cases of foreign cybersquatting as to which the 'in rem' provision will be both applicable and constitutional. Instead the ACPA 'in rem' provision is notable primarily for its aggressive assertion of jurisdiction, leading us to consider the (often overlooked) role of realspace sovereigns in the regulation of the domain names system. By mapping the logical control over the domain names system-the distributed hierarchy that is the basis of the system's design-onto realspace territory, the potential for sovereign regulation of the system becomes apparent. We argue that the regulatory significance of geography, and the essentially arbitrary nature of the present territorial locations of the key components of the domain name system implies the future segmentation of the domain name system, and the resulting dramatic decrease in its value. Accordingly, we argue that realspace sovereigns (and especially the United States) have strong interests in avoiding segmentation, and thus must seek to coordinate the regulation of the system."