As the noted social critic H. L. Mencken once declared, “The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, most of them imaginary.”

In A Dangerous World? Threat Perception and U.S. National Security, a new book edited by Christopher A. Preble and John Mueller of the Cato Institute, a number of scholars ask to what degree the United States is threatened, examining not only the multiplicity of supposed dangers, but also the wisdom or folly behind the measures that have been proposed to deal with them. Paul Pillar, a visiting professor at Georgetown University’s Center for Security Studies, observes that “substate” threats — from terrorism to crime — pale in comparison to traditional threats posed by states. He urges readers to reexamine their preconceived notions of what is required to keep the United States both safe and free. Noting a disconnect between the severity of threats and how much alarm they generate, he voices dismay at the tendency to identify monsters abroad and “conceive of America’s place in the world largely as one of confrontation against them.” In the end, he cautions that the capacity of the United States to curb substate conflict is usually very limited. In fact, intervention itself can be counterproductive.

Eugene Gholz, associate professor of political science at the University of Texas at Austin, explores the economic effects of warfare. Although war itself has many highly undesirable effects, he finds that overseas tensions do not necessarily harm the U.S. economy. Daniel Drezner, professor of international politics at Tufts University, finds some merit in the global public good provided by overwhelming U.S. primacy. However, it is not obvious that military power is the primary driver of the benefit, while sustaining it comes at great cost.

Other contributors include Peter Andreas of Brown University on “Transnational Crime as a Security Threat,” Martin Libicki of the RAND Corporation on “Dealing with Cyberattacks,” and Mark G. Stewart of the University of Newcastle on “Climate Change and National Security.” Although the world will never be free from dangers, we should aspire to understand them clearly. By chipping away at the common perception that the world is getting more dangerous each day, the contributors to this volume attempt to tame the tendency to overreact.