Protecting a nation or community against acts of terrorism can come at the expense of rights to liberty and privacy. This chapter identifies the range of security interventions that intrude on these rights, from relatively benign passive screening systems at one end to torture on the other. It describes the historical foundations of the problem and offers examples of interventions that involve a tradeoff between security and liberty, those that enhance security without an adverse effect on liberty, and those that reduce both security and liberty. It then deals with two specific interventions: profiling to detect terrorists and the USA Patriot Act. It concludes by considering frameworks for identifying and organizing key variables to assist in weighing the effectiveness of alternative interventions and their costs as invasions of the public's rights to privacy and freedom.

The Problem and Its Historical Precedents

Perhaps the most fundamental problem raised by the threat of terrorism is this: How can liberal democratic society and all its fruits be protected against terrorism without intruding on the very properties of liberal democracy that make it worth protecting? The basic problem was raised in the eighteenth century in a frequently quoted statement widely attributed to Benjamin Franklin, emphasizing the liberty side of the coin: “Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety.”