1. War Can Be in the Signaling Effect:
War and Bargaining with Bilateral Uncertainty by
Jean-Pierre Langlois, San Francisco State University
Catherine langlois, Georgetown University
Prepared for the Peace Science Conference in Tempe, November 3, 2017

2. How do states at war exchange information?
In the game models developed by Filson and Werner ( 2002 ) Slantchev(2003) or Powell (2004), states observe the outcome of battle and use bargaining to screen the other side

3. These Models Assume Asymmetric Information
This specializes the roles of the players
The uninformed player screens the other for strength by making offers tailored to the weakest still standing.
The informed side does not speak or if it does (Slantchev) it reveals its type.

4. With asymmetric information the nature of an offer is unambiguous
An offer from the uninformed player screens and does not signal because the informed player knows about him.
The informed player weighs the payoff from getting screened to making a war ending offer to the uninformed rival. An offer from him can signal his type but does not screen because he does not need to.

5. How your offer affects my beliefs is what matters
When we introduce bilateral uncertainty the nature of an offer can become ambiguous
Is my offer to you meant to screen you for strength?
Or is it a signal of my weakness?
Interpreting the informational content of an offer is now a matter of interpretation
How your offer affects my beliefs is what matters

6. We develop a war and bargaining model following Powell (2004) but assume bilateral uncertainty
We exhibit an equilibrium in which neither side makes concessions to the other in war because such concessions will be interpreted as a signal of weakness.
Our work underscores the importance of interpretation and resulting beliefs when the informational content of a bargaining offer is ambiguous.

13. A Perfect Bayesian Equilibrium
Under a condition on parameters that involves:
Concern for the future (there must be enough)
Uncertainty (the difference between the strongest and the weakest), war costs and the initial sharing of the asset in combination.
The following is a PBE

20. fighting to the finish is acceptable
Intuitively, for no concession to be a possible equilibrium players must find that the prospect of
fighting to the finish is acceptable
As uncertainty on the probability of victory costs increases, no concession will be an
equilibrium over an increasing range of parameter values