Nearly 15 years has elapsed since the World Commission on Environment and Development—the so-called Brundtland Commission—popularized the idea of “sustainable development.” The phrase turned out to be unusually slippery, providing both political cover and ammunition for almost anyone engaged in debates about the global environment and/or development. Indeed, scholars and policymakers of all theoretical or ideological stripes found creative ways to employ the phrase “sustainable development” to support a wide array of arguments in these discussions.