This paper deals with collective decision making within a group of independent states. The right to choose the public policy is delegated from the central authority to one of the states through a bidding procedure among the group state members. We identify the following tradeoff: competition among states yields higher transfers to the central authority, but the outcome tends to be less efficient than what it is when states negotiate prior to the decision making process. We extend and illustrate the model by means of a public good game involving several heterogeneous states.