Two-Level Game Analysis

A win-set is the set of all possible Level I (international) agreements that a given country's domestic constituency would ratify — that is, every deal that a sufficient domestic coalition prefers to the no-agreement reversion point. Its boundaries are set by domestic preferences, the institutional ratification rule (such as a simple majority or supermajority), and the negotiator's own strategies. An international agreement is feasible only when the negotiating countries' win-sets overlap.

A negotiator with a small win-set — constrained by a hostile legislature or mobilized interest groups — can credibly claim that only deals close to its own position could ever be ratified at home. This 'tied-hands' or Schelling-style commitment forces a flexible counterpart to concede, because any deal outside the constrained negotiator's narrow win-set would simply collapse in ratification. The catch is that if the win-sets fail to overlap at all, the same rigidity produces no agreement, so domestic weakness aids leverage only when some overlap remains.

Both rely on the spatial idea that change requires the consent of actors whose agreement is necessary, and both use intersection-of-preferences logic. Veto player theory analyzes domestic policy change as a function of the winset of the status quo across a system's veto players, while the two-level game embeds that domestic ratification game inside an international negotiation: the Level II ratifiers act much like domestic veto players whose joint acceptable set defines the country's win-set. Two-level analysis thus extends veto-player reasoning to the interaction between domestic ratification and interstate bargaining.