accountability, and oversight mechanisms necessary to keep counterterrorism activities within view of the democratic process.
In general, substantive privacy rules involve restrictions on access to and use of personal information by the government. Such restrictions are a means of limiting the power of government and private-sector institutions. For example, in the spirit of the bedrock constitutional principle of limited government, the Fourth Amendment defines limits on government power by establishing individual rights against certain intrusions. It protects privacy not only because Americans value individual liberty as an end in and of itself, but also because their collective political, cultural, and social flourishing depends on it. To this end, privacy protections generally take the form of boundaries between individuals and institutions (or sometimes other individuals). These boundaries may limit the information that is collected (in the case of wiretapping or other types of surveillance), how that information is handled (the fair information practices that seek care and openness in the management of personal information described in Box G.1), or rules governing the ultimate use of information (such as prohibitions on the use of certain health information for making employment decisions).
Today, a variety of new technologies put pressure on existing boundaries between individuals and large institutions. New surveillance and analysis technologies used in the service of counterterrorism goals are effective precisely because they give investigators new capabilities that erode the boundaries previously established between individuals and governments. For example, data mining techniques operating over large collections of information, each element of which is not particularly revealing, may yield detailed profiles of individuals, and location-aware sensor networks allow collection of tracking information on large numbers of individuals when most of them are not actually suspected of any crime at the time of data collection. New identification documents (including driver’s licenses and passports) will collect biometric information in digital form on most of the population, marking the first time the digital images of the faces of the population will be available for law enforcement use. All of these technologies are susceptible to a wide variety of different uses, with widely varying intrusiveness.
Many of the privacy questions facing the information age society are