Can third parties do more than foster temporary, unstable ceasefires? Without perpetually holding the belligerents at arms’ length via heavily militarized buffer zones? Is it possible to make peace self-enforcing at a reasonably low cost?
Recent work on conflict management suggests not. Less intrusive approaches to mediation, such as information provision, fail to solve the problem that poses an obstacle to efficient negotiate between the belligerents in the first place. More intrusive approaches such as deploying armed peacekeepers are often successful, at least if they come after a conflict ends, but entail great costs. You want lasting peace on the cheap? Good luck with that.
Writing with Anna Pechenkina, I have argued that the consensus view may be too negative. Third parties can raise the effective cost of war by promising to provide subsidies if and only if war is avoided. But even that does not solve the underlying problem. Subsidized peace may persist, provided the provision of the subsidies persists, but it is not self-enforcing.
In a fascinating paper, Rob Carroll offers some optimism. He demonstrates formally that third parties can remove the risk of war, in a fundamental sense, by engineering transfers of economic and military resources in such a way that the natural outcome of trade will reflect the expected outcome of war. Thus, neither side will stand to gain from fighting and will not be expected to do so. In equilibrium, the two sides make their own peace—but they would not have done in the absence of mediation.