The tendentious semantics that surround the word terrorism have infected much debate about counterterrorism, and have involved other words in that debate. Probably the leading example is the perennial question of “Is it crime, or is it war?” None of the enormous verbiage devoted to that question has shed any light on, or advanced public understanding of, the nature of terrorism or how to deal with it. Of course terrorism is criminal; it involves actions such as killing or assaulting innocent people, which are covered by ordinary criminal statutes whether or not there are any laws specifically defining terrorist crimes. And if the use of military force is one of the tools available for countering terrorism — and it is — then one can choose to call it war as well. The application of either or both of these labels, or any other label, does absolutely nothing to resolve the issues of ethics and practical effectiveness, and not only of legality, raised by such difficult questions as how to handle detained terrorist suspects and whether to conduct targeted killings of terrorists still at large. Labels cannot substitute for analysis and principled discussion.