POL SCI: Rationalist Explanations for War

Central Puzzle:

Wars are costly, and yet wars recur

Ex-post, war is ________

inefficient:-There are (ex-ante) bargains that could be reached, where leaders could gain the same final outcome with a negotiated settlement, while avoiding the costs of war

Why does war occur when ex ante bargains exist? 3 types of arguments:

-War caused by irrational people-Costs of war not suffered by leaders-Even rational leaders who consider the risks and costs of war may end up fighting (�rationalist explanations�)

5 Rationalist Explanations for War:

-Anarchy-Rational preventive war-The expected benefits are greater than the expected costs-Rational miscalculation/disagreement about relative power-Rational miscalculation due to lack of information


Not a sufficient explanation

Positive Expected Utility:

Explanations fail to address the question of how or under what conditions it can be possible for two states both to prefer the costly gamble of war to any negotiated settlement

Fearon�s Model:

-Two states: A and B-X = A�s share of the territory 0________________1 x iB iA-iA and iB: A�s and B�s ideal points-A�s utility = X-B�s utility = 1 � X-Assume both countries are risk neutral

The Model:

p = A�s probability of winning a war against BcA and cB = A�s and B�s costs of war-EUA(war) = p(1) + (1-p)(0) � cA = p � cA-EUB(war) = p(0) + (1-p)(1) � cB = 1 � p - cB

Ex Ante Bargaining Range: Requires three assumptions:

-States know there is one true probability p-States are risk neutral or risk averse -A continuous range of settlements exists

Rational Miscalculation:

Rational miscalculation due to disagreement about relative power or lack of information:-Neither goes far enough/ works by itself

To avoid war�s ex post inefficiency:

leaders have incentives to share private information

To explain how war could occur between states led by rational leaders we needto explain

what would prevent them from sharing such private information

Explanation 1: Incentives to Misrepresent:States have incentives to...

withhold private information because they wish to obtain a favorable negotiated settlement:-Incentives to exaggerate their true willingness to fight or their true capability

Explanation 2: Commitment Problems:

Even when there is no private information (and both sides agree on the bargaining range), war occurs because one side cannot commit to uphold the bargaining

Commitment Problems: One side cannot commit to uphold the bargain when:

-A large first strike advantage exists-When one side�s probability of winning in the next period exceeds its probability of winning in the first period-If the bargain would drastically increase one side�s future bargaining leverage