Deterrence and compellence were foundational strategies during the Cold War. They have made a comeback in the light of widespread fears of an aggressive Russia, more assertive China, and always troublesome North Korea. There are notable differences between the present and the past. Terrorism is the most immediate security threat to the West, foreign adversaries are increasingly non-state groups and movements, and chaos in North Africa and the Middle East has brought a flood of refugees to Europe. Globalization has significantly increased the mobility of pathogens, and with it the possibility that a newly evolved virus in East Asia or Africa could devastate populations worldwide. Most threatening of all in the longer term is global warming and the economic dislocation, water shortages, and domestic and international conflicts it is likely to provoke. Threat-based strategies are not relevant to these problems. But they are pertinent to more traditional kinds of conflicts—or thought to be—by those who make or seek to influence policy—and to combatting terrorism as well. Arguments in favor of them frequently invoke the so-called lessons of the Cold War or other past conflicts. It is worth revisiting these lessons, and all the more so because I think they are wrong. Toward this end I offer a critique of deterrence and compellence, based on the same cases but better historical evidence.