Technical information is a key aspect of governance responses to complex global problems. International relations scholarship emphasizes the role of science and scientific communities for advancing cooperation in a range of issue areas-from public health and the environment to trade, control of nuclear substances, and telecommunications. This literature demonstrates that causal ideas, supported by sufficient political consensus, can be critical in determining the likelihood and form of multilateral agreements.  International consensus about policy-relevant knowledge, however, is often difficult to achieve. Technical solutions create distributional problems and incentives to withhold, manipulate, and mistrust information. The economic implications of cooperative agreements for multiple sets of actors can further interfere with the process of effective knowledge communication. One salient question that emerges is how to structure the supply of expertise to enhance its policy relevance and uptake across diffe rent interests, beliefs, and cultures.
In this article I address concerns about the sources of credibility and policy influence of expert information. I focus on environmental governance, which exemplifies an issue area that relies heavily on domestic and transnational expertise. I examine environmental assessments  as a component of the knowledge-generating process and consider the institutional characteristics of assessments that make them an effective tool for consensus building in environ mental politics. I argue that to serve as a basis for cooperation, assessments need to be politically engaged so as to facilitate a dialogue between experts and relevant political actors. A structure that allows for broad political authorization enhances the credibility, adequacy, and legitimacy of technical information and thus its policy relevance and effectiveness in international environmental governance. I also take into consideration the tension between political consultation in an expertise process and its credibility among the scientific community. A purely technocratic view of science would emphasize the need for expert neutrality and isolation from political interests as a condition for scientific quality and policy effectiveness. I explore this dilemma and conclude that despite the apparent tension between public involvement and scientific integrity, discounting the political dimension of knowledge can be detrimental to its effectiveness as a tool for international collaboration. This conclusion calls for expertise structures and institutions with the capacity to accommodate public communication while maintaining the boundary of technical excellence.
In the next section I develop the argument in detail. The analysis identifies the main mechanisms through which consultation with relevant actors enhances the uptake of expert advice and its influence on transnational governance. The environmental negotiations within the context of the European Union (EU) enlargement to Central and Eastern Europe (CEE) provide empirical ground for evaluating the relevance of the theoretical argument. I consider the role of a range of economic assessments, characterized by different structures, in the preparation of Poland and Bulgaria for the approximation and implementation of EU environmental legislation. By establishing the importance of political involvement in assessment processes, the case studies set the stage for addressing the question of how to achieve such political consultation while maintaining high technical credibility. In the conclusion, I engage this problem in a discussion of the policy implications of the theoretical and empirical analysis.
Expertise Structure and Policy Relevance
Is knowledge best engaged in decisionmaking from the ivory tower of the expert establishment, or through the active involvement of relevant political viewpoints? This debate dates back to Plato and Aristotle and persists in U. …