The Zapatista rebels of southern Mexico have achieved considerable success both in maintaining themselves against unlikely odds and in coming to agreement with the Mexican government on issues affecting indigenous rights and identity. At the same time, a central demand, both of the Zapatistas and the indigenous movement which they have helped to revitalize, namely revision of the 1992 constitutional reforms affecting corporate claims to land and the possibility of further land reform, has been roundly rejected by the government. The paper explains both Zapatista achievements and the limits to ethnic bargaining evident in the negotiations to date through an analysis of the dynamic process by which both sides came to the negotiating table and shaped and reshaped the rules of the bargaining game. It draws on social movement theory to show how the Zapatistas in particular were able to overcome the ``asymmetry of internal conflict'' and frame the issues, enlarging its base of support to a national level. At the same time, specifically indigenous issues could be resolved much more readily than the larger concerns, including those surrounding landholding, which motivated the rebellion. The shifting political context had much to do with the government's willingness to negotiate; but the Zapatista's skill at assembling a national constituency, attracting international attention, and framing the issues were decisive in achieving accords on indigenous rights. Nevertheless, in the absence of a ``mutually hurting stalemate,'' government negotiators could continue to reject Zapatista demands on issues reaching beyond strictly ethnic concerns.