 Bargaining views call a regime legitimate for an individual when it maximally advances her interests. Bargaining suggests a negotiation that yields a stable equilibrium of opposing forces: each person achieves as much as she can, consistent with the needs of others. The most prominent example of a bargaining theory is David Gauthier’s contractarianism. Gauthier argues that citizens need a social morality to secure social cooperation. We identify moral and political norms as justified when it is instrumentally rational for each agent to accept them.