The Internet has reached a critical point. The world is running out of Internet addresses. There is a finite supply of approximately 4.3 billion Internet Protocol (IP) addresses--the unique binary numbers required for every exchange of information over the Internet--within the Internet's prevailing technical architecture (IPv4). In the 1990s the Internet standards community identified the potential depletion of these addresses as a crucial design concern and selected a new protocol (IPv6) that would expand the number of Internet addresses exponentially--to 340 undecillion addresses. Despite a decade of predictions about imminent global conversion, IPv6 adoption has barely begun. IPv6 is not backward compatible with IPv4, and the ultimate success of IPv6 depends on a critical mass of IPv6 deployment, even among users who don't need it, or on technical workarounds that could in turn create a new set of concerns. Protocol Politics examines what's at stake politically, economically, and technically in the selection and adoption of a new Internet protocol. Laura DeNardis's key insight is that protocols are political. IPv6 serves as a case study for how protocols more generally are intertwined with socioeconomic and political order. IPv6 intersects with provocative topics including Internet civil liberties, U.S. military objectives, globalization, institutional power struggles, and the promise of global democratic freedoms. DeNardis offers recommendations for Internet standards governance based not only on technical concerns but on principles of openness and transparency and examines the global implications of looming Internet address scarcity versus the slow deployment of the new protocol designed to solve this problem.