In this book, Matthew J. Hoffman attempts something quite ambitious: a two-stage analysis in which he first designs a formal model to test Martha Finnemore and Kathryn Sikkink's constructivist model of a norms life cycle, and a subsequent application of the insights generated to an empirical case. Although he does not quite pull it off, it is an effort worthy of attention and further development. On a stylistic note, the text contains an irritating amount of repetition that a good copy editor should have questioned.

Hoffman's general question is “who participates in global governance,” informed by the observation that over the course of the negotiation of the treaty to prevent ozone depletion, the participation norm changed from a restricted, North-only negotiating format to one demanding universal participation. After reviewing alternative theoretical approaches, Hoffman finds the norm life-cycle approach most compelling. He then sets up an agent-based model designed to test aspects of that model, particularly its attribution of a crucial role to a norms entrepreneur. Constructivism and agent-based modeling share a focus on the interactive dimensions of politics, in which actors' actions affect each other's behavior, eventually contributing to large-scale pattern shifts. By attributing heuristics—rules of thumb—to the units in the system, modelers use simulations to build a dynamic environment in which to test conditions under which such adaptations might take place. Hoffman's findings strongly support the importance of an entrepreneur under conditions of relatively high social complexity and in the presence of numerous other stimuli (noise) in the system. He proposes a modification to the norm life-cycle approach that takes into account social conditions, and then asks whether it can explain (and, by implication, attribute robustness to) the shift that took place in expectations about participation in global treaties.

The empirical account traces the role of Mustafa Tolba, executive director of the United Nations Environment Program, during negotiations of successive framework treaties and protocols related to ozone depletion and then climate change. Hoffman contends that Tolba's entrepreneurship on behalf of the developing world persuaded key actors that global treaties should be premised on universal participation. By the early nineties, support for this position produced a “lock-in” around a new norm of universal participation, such that by the time that negotiations for a Framework Convention on Climate Change took place, it was taken for granted.

The empirical section tells the story of how the argument for expanding participation in global negotiations and governance gained acceptance between the negotiation of the Montreal Protocol and the Climate Change Convention. The account has serious shortcomings that make it unconvincing, though not implausible. These relate to a) the treatment of “universal participation,” b) a shallow (and sometimes erroneous) understanding of the “southern” position, and c) a failure to consider alternative explanations.

Hoffman's “universal participation” refers to treaty negotiations. This usage is somewhat at odds with what is more commonly implied by the phrase—the effort to have all states sign and ratify an agreement. The change in emphasis deserves at least a mention. The United Nations Convention on the Law of the Sea, opened for signature in 1982, sought universal participation, a process that continued over decades. The author refers to this precedent only in passing.

While noting the role of large developing nations in the production of greenhouse gasses, Hoffman otherwise treats the developing world as a homogenous entity. He refers to their lack of interest in the ozone negotiations and attributes the participation of 37 southern states in the production of the Montreal Protocol to Tolba's persuasion, assuming that their interest is only continued access to chlorofluorocarbons (CFCs). But in fact there were three groups of countries in Montreal, not two: producers of the technology, producers of equipment using the technology (air conditioners, refrigerators, etc.), and consumers of the latter. The second group, which included large developing countries like Brazil and India, had distinct interests because they had paid large sums to northern firms for the rights to use the technology; northern countries also feared that a North-only treaty would allow Brazil and India to continue producing and exporting cheaper goods using CFCs. This is the group for which technology transfer was the most important.

The author considered few alternative explanations for expanded participation, focusing on three: rationality, excluded because efficacy is enhanced by restricting participation; requirements of the science itself, excluded because scientists take a variety of positions on the subject; and actions of a hegemon (the United States), excluded because the evidence, if anything, points the other way. Conspicuously absent were powerful contextual factors like the collapse of the Soviet Union, the explosion of normative discourse about democracy and participation, and transformations in communications technology that facilitated expanded participation. Also absent was the growing participation (and interaction) of nongovernmental actors in both developing and developed countries, fueled by a whole series of United Nations theme conferences reaching back to the UN Conference on the Human Environment in Stockholm in 1972.

Although there is a significant gap between the theoretical ambitions and the empirical analysis of Ozone Depletion and Climate Change, the shortcomings of the latter do not necessarily diminish the interest of the former. Hoffman's findings that entrepreneurship is especially important in situations of high social complexity and where there is a lot of noise in the system are suggestive and valuable, and deserve attention from scholars interested in the workings of norms in international politics. Tolba's entrepreneurial role was undoubtedly important, and an exploration that took into account a larger context would have been valuable. A norm favoring democratization of access to global negotiations and governance compacts may indeed be gaining robustness. Whatever their plausibility, however, the empirical account fails to convince me of the causal weight of norm entrepreneurship here, or that moves made in the negotiation of these two treaties were the crucial sites in which this occurred.