Christopher Bronk, writing in First Monday:

Considerable debate surrounds the issue of wiretapping as a tool for the collection of intelligence in combating trans–national organizations employing terror tactics in pursuit of their political agendas. This paper argues that the language used to frame this debate is outmoded. At root conventional wisdom of the wiretapping issue in the United States is framed by a general consensus that fails to account for now ubiquitous digital means of communication. In addition, the issue of information security, the protection of computer networks, government and private alike, but often tied in some way to critical infrastructure, is inextricably linked to digital eavesdropping. The author argues that while attempts to understand the totality of network activity may be of great value in protection of critical infrastructure, this webtapping presents potentially grave implications for individual liberties and may produce limited payoffs in defeating terror organizations or cyber–attackers.

From the archive:

Said Diffie, "The future will be a golden age for intelligence."

See also, this important paper by Bellovin, Blaze, Diffie, Landau, Neumann, and Rexford:

Architecture matters a lot, and in subtle ways.