Abstract: The current context of a ‘war against terrorism’ raises the question whether international humanitarian law should govern a state’s actions in an armed conflict against a foreign terrorist organization. Depending on the configuration of the conflict, including the response of the foreign state from whose territory the terrorists operate, existing treaties may already apply to the military operations. The limited protections they impose, though not originally designed with such a conflict in mind, do not unduly hinder defence against international terrorism. Restricting counterterrorist operations is justified, in part by bedrock human rights of the terrorists themselves, but more strongly by the rights of innocent civilians exposed to counterterrorist violence.