Fourth Amendment limits on national identity cards

In the past three years there have been serious calls for a national identity system whose centerpiece would be some form of national identity card. This chapter analyzes the Fourth Amendment issues raised by two major features of any likely national identity system: requests or demands that individuals present their identity cards; and governmental collection, retention, and use of personal information to be used in identity checks. These issues are evaluated in several different contexts in which they might plausibly arise. The chapter concludes that, while the Fourth Amendment might bar certain practices and block others depending on their purposes, it would be possible to have a constitutional national identity card system of a fairly comprehensive type. Even where an identity system would not strictly run afoul of the Fourth Amendment, however, an analysis of the interests that the Amendment is designed to protect provides an insight into the price in privacy and liberty a national identity system would exact. The chapter also indicates how these effects might be mitigated somewhat in the system's design. This chapter thus aims to illuminate not only what kind of national identity system the U.S. lawfully could have, but how it might be devised, and, implicitly, whether we want to have one at all.