A few days before the start of the confirmation hearings for General Michael Hayden, who has been nominated by President Bush to be the head of the C.I.A., I spoke to an official of the National Security Agency who recently retired. The official joined the N.S.A. in the mid-nineteen-seventies, soon after contentious congressional hearings that redefined the relationship between national security and the publicøs right to privacy. The hearings, which revealed that, among other abuses, the N.S.A. had illegally intercepted telegrams to and from the United States, led to the passage of the 1978 Foreign Intelligence Surveillance Act, or FISA, to protect citizens from unlawful surveillance. [...]
The N.S.A. also programmed computers to map the connections between telephone numbers in the United States and suspect numbers abroad, sometimes focussing on a geographic area, rather than on a specific personøfor example, a region of Pakistan. Such calls often triggered a process, known as øchaining,ø in which subsequent calls to and from the American number were monitored and linked. The way it worked, one high-level Bush Administration intelligence official told me, was for the agency øto take the first number out to two, three, or more levels of separation, and see if one of them comes backøøif, say, someone down the chain was also calling the original, suspect number. As the chain grew longer, more and more Americans inevitably were drawn in.[...]
The legal implications of chaining are less clear. Two people who worked on the N.S.A. call-tracking program told me they believed that, in its early stages, it did not violate the law. øWe were not listening to an individualøs conversation,ø a defense contractor said. øWe were gathering data on the incidence of calls made to and from his phone by people associated with him and others.ø Similarly, the Administration intelligence official said that no warrant was needed, because øthereøs no personal identifier involved, other than the metadata from a call being placed.ø
