1 Bargaining over the Caspian Sea- the Largest Lake on the Earth Majid Sheikhmohammady 1 and Kaveh Madani 2 1 Department of Systems Design Engineering, University of Waterloo, Ontario, Canada; Email: msheikhm@engmail.uwaterloo.ca 2 Department of Civil and Environmental Engineering, University of California, Davis, U.S.A.; Email: kmadani@ucdavis.edu Abstract The Caspian Sea is considered by some to be the largest lake in the world. This multinational water body is the subject of one of the world’s most intractable disputes, involving Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. The conflict over the legal status of the Caspian Sea emerged after the collapse of the Soviet Union and has not been resolved yet. This paper intends to provide some insights into the conflict and predict the most possible outcomes of the negotiations based on Social Choice rules and Fallback Bargaining procedures. In this study, the five options for resolving the conflict which has been suggested during the negotiations are introduced and discussed. Some well-known social choice rules including Condorcet Choice, Borda Scoring, the Plurality Rule, Median Voting Rule (MVR), Majoritarian Compomise (MC) and Condorcet’s Practical Method (CPM) are applied to find the “socially optimal” resolutions of this conflict. Then some different versions of Fallback Bargaining methods which seek minimizing the maximum dissatisfaction of any bargainer are applied to predict the outcome of the negotiations. Finally, the socially optimal resolutions are compared with Fallback Bargaining methods’ results and the advantages and disadvantages of each method are discussed. Keywords: Caspian Sea, conflict, multilateral negotiations, social choice rules, fallback bargaining World Environmental and Water Resources Congress 2008 Ahupua'a © 2008 ASCE Copyright ASCE 2008 World Environmental and Water Resources Congress 2008: Ahupua'a