Stakeholder negotiation is an increasingly important policymaking tool. However, relatively little is understood about the relationship between the structure of the negotiating process and the effectiveness with which stakeholders can pursue their individual interests. We apply the Rausser- Simon multilateral bargaining model to a specific negotiation process involving water storage capacity and use in the upper Adour Basin in southwestern France. We focus on a coalition of three stakeholder groups with aligned but distinct interests. In addition to the standard indices of bargaining powerԴhe distribution of political weights (ܡccessݩ and players٠utilities if an agreement is not reached, our analysis identifies other less obvious sources of power. First, a coalition member may benefit when his access is reduced if the redistribution increases the access of another coalition member who has a more favorable ܳtrategic location.ݠSecond, the interests of the coalition as a whole will usually, but not always, be advanced if its members cede access to a pokesmanݠrepresenting their common interests. However, some members may be adversely affected. Third, restricting the extent to which coalition members can make proposals that further their own individual interests at the expense of other coalition members will usually, but not always, harm the coalition as a whole.