Mowing the Grass

• In Event: Formal Models of (Civil) War

Abstract

Mowing the grass describes a counterterrorism policy, where after a period of military restraint, a government attacks to destroy the capabilities of terrorist group with the goal of achieving a period of quiet as the group recovers. If the group expects its capacity to be destroyed, why build capabilities? If the government expects that the terrorists will rebuild, why continue to attack? I analyze an infinite-horizon model where a terrorist group can endogenously build capacity in the face of potential government attacks, where capacity is an evolving stock. The model highlights that terrorists and governments may have incentives to randomize even in a sequential model of complete information. I use the model's mixed-strategy equilibrium to rationalize data in the Israeli-Palestinian conflict describing the evolution of Hamas Qassam rocket attacks, allowing me to estimate key parameters of interest. Using the fitted model, I study how levels of violence would change if governments became more patient or had larger costs of attacking terrorist groups.

Author

• Michael Gibilisco, California Institute of Technology