Are Intrastate Peacekeeping Operations Less Likely to Succeed? Some Statistical Evidence

United Nations peacekeeping operations (PKOs) in intrastate conflicts have historically been much more war prone than PKOs in interstate conflicts. On the basis of this and other pieces of evidence, PKOs in intrastate conflicts are commonly claimed to have an inherently lower success rate than operations in interstate conflicts. By “success” is here meant absence of war rather than mandate fulfilment or some other criterion. This paper assesses this claim by formulating and with statistical techniques testing hypotheses that are implied by the claim. The hypotheses suggest differences in inertia for peace as well as war across the two types of PKOs, and are tested on a data set that includes all PKOs 1948-2000. A first-cut statistical test finds that inertia of peace is very large for both types of operations, but there is meanwhile no robust evidence that the inertia of war is larger in intrastate PKOs. This means that there is no robust evidence for the claim that intrastate PKOs are inherently less likely to succeed. A possible explanation for the historically larger war proneness of intrastate PKOs is the generally large inertia of war, combined with the less than benevolent initial environment in which many intrastate operations are deployed