I have just uploaded a draft of a new essay, Updating the Foreign Intelligence Surveillance Act, forthcoming in a symposium issue of the University of Chicago Law Review. It's a short article, about 22 pages. Here's the abstract:

This essay argues that the Foreign Intelligence Surveillance Act should be restructured to account for changes in communications technology and Fourth Amendment law since FISA's enactment in 1978. FISA reflects the person-focused assumptions of 1970s-era technology and constitutional law. At that time, foreign intelligence monitoring necessarily focused on subject identity and location. Although some modern investigations track this traditional approach, many do not; investigations involving packet-switched networks often start with data divorced from any known person or location. FISA should be amended to create two distinct authorities for surveillance: data-focused authorities when the identity and/or location of the subject are unknown, and person-focused authorities when the identity and/or location are known. A two-pronged approach can best implement the goals of foreign intelligence investigations given the realities of modern communications networks.