Mowing the grass

Abstract

Mowing the grass is a cyclical pattern in counterterrorism campaigns where governments attack to destroy terrorist capacity, thereby achieving a period of quiet as groups recover. If groups expect their capacity to be destroyed, why build their capabilities in the first place? I analyze an infinite-horizon dynamic game where a group endogenously builds capacity in the face of potential attacks and capacity is an evolving, persistent variable. The model highlights that terrorist groups and governments have incentives to create strategic uncertainty and thus explains attack cycles without punishment strategies, revenge preferences or imperfect/incomplete information. I calibrate the model to time-series data in the Israeli–Palestinian conflict describing rockets fired from Gaza. The results illustrate a peace-making dilemma: altering the government’s incentives will have comparatively minimal effects on long-term conflict dynamics, whereas changing the terrorists’ incentives to acquire capacity would either increase the frequency of high-capacity terrorism or government attacks.