Two-Level Game Theory

Two levels of play

In "Diplomacy and Domestic Politics: The Logic of Two-Level Games" (1988), political scientist Robert Putnam criticized studies that treated international and domestic politics separately. Using the 1978 Bonn summit as a case, he argued that leaders build tentative agreements with their counterparts at the international table (Level I) and must then get them ratified at home (Level II) by legislatures, bureaucracies, interest groups and voters. Negotiators watch both tables at once and calculate how moves at one affect the other. "Ratification" here means not only formal legislative approval but substantive acceptance by domestic actors. The theory belongs to a broader effort, like Peter Gourevitch's (1978) "second image reversed," to analyze domestic–international interaction systematically.

Win-sets and the paradox of weakness

The central concept is the win-set: the set of Level I agreements that could be ratified at Level II. Agreement is possible only if the two sides' win-sets overlap, and larger win-sets make agreement more likely. Win-set size depends on the distribution of domestic interests and coalitions, ratification rules such as the US Senate's two-thirds requirement, and negotiators' strategies. The paradox is that a side with a narrow win-set because of domestic constraints may bargain more effectively: if the claim that "Congress will never pass anything more" is credible, the other side must concede. This echoes Thomas Schelling's (1960) insight in The Strategy of Conflict that having one's hands tied can be an advantage, and is known as the Schelling conjecture. From a game-theoretic standpoint, negotiators may also ally with opponents inside the other country or use side payments to widen its win-set.

Extensions and critiques

Evans, Jacobson and Putnam's Double-Edged Diplomacy (1993) applied the theory to eleven cases spanning trade, security and monetary negotiations. Iida (1993) and Tarar (2001) showed with formal models that the advantage of a narrow win-set can shrink under incomplete information, and Jongryn Mo (1995) found that outcomes depend on whether the negotiator holds a veto. Helen Milner (1997) argued that divided government makes cooperation harder, and James Fearon's (1994) audience-cost theory similarly shows domestic politics shaping crisis behavior. In Korea the framework is widely used to analyze the KORUS FTA, rice-market opening and defense cost-sharing talks. Critics note that the approach is more an analytic metaphor than a precise predictive theory and that it treats national interests and preferences as fixed (Moravcsik, 1993).

FAQ

What is two-level game theory in simple terms?

Diplomats negotiate with other countries while also persuading their own parliament and public, so they are effectively playing two negotiations at once.

Why can strong domestic opposition help in negotiations?

If the claim that any further concession would fail at home is credible, the other side has to give ground. This is called the Schelling conjecture.

Sources reviewed: 2026-10-26

References

1. Putnam, R. D. (1988). Diplomacy and domestic politics: The logic of two-level games. International Organization, 42(3), 427–460.
2. Evans, P. B., Jacobson, H. K., & Putnam, R. D. (Eds.). (1993). Double-Edged Diplomacy: International Bargaining and Domestic Politics. Berkeley: University of California Press.
3. Schelling, T. C. (1960). The Strategy of Conflict. Cambridge, MA: Harvard University Press.
4. Milner, H. V. (1997). Interests, Institutions, and Information: Domestic Politics and International Relations. Princeton: Princeton University Press.
5. Moravcsik, A. (1993). Introduction: Integrating international and domestic theories of international bargaining. In Evans et al. (Eds.), Double-Edged Diplomacy (pp. 3–42).
6. Iida, K. (1993). When and how do domestic constraints matter? Journal of Conflict Resolution, 37(3), 403–426.
7. Tarar, A. (2001). International bargaining with two-sided domestic constraints. Journal of Conflict Resolution, 45(3), 320–340.
8. Mo, J. (1995). Domestic institutions and international bargaining: The role of agent veto in two-level games. American Political Science Review, 89(4), 914–924.
9. Fearon, J. D. (1994). Domestic political audiences and the escalation of international disputes. American Political Science Review, 88(3), 577–592.
10. Gourevitch, P. (1978). The second image reversed. International Organization, 32(4), 881–912.
11. Pahre, R. (Ed.). (2006). Democratic Foreign Policy Making: Problems of Divided Government and International Cooperation. New York: Palgrave Macmillan.
12. Da Conceição-Heldt, E., & Mello, P. A. (2017). Two-level games in foreign policy analysis. In Oxford Research Encyclopedia of Politics. Oxford: Oxford University Press.
13. Bueno de Mesquita, B., Smith, A., Siverson, R. M., & Morrow, J. D. (2003). The Logic of Political Survival. Cambridge, MA: MIT Press.