This is a multi-part (due to length) comment intended to highlight the information provided by the expert David Kris in his recent paper "Modernizing The Foreign Intelligence Surveillance Act" which discusses the history of FISA and international phone calling technology, as well as the Protect America Act, the pending Senate Intelligence Committee's FISA Amendments Act and the House's RESTORE Act. Kris's clear and comprehensive paper (from which I'm excerpting below) is available for downloading here (I highly recommend reading it in full):

Http://www.brookings.edu/~/media/Files/rc/papers/2007/1115_nationalsecurity_kris/1115_nationalsecurity_kris.pdf

Kris provides excellent information, but it may be hard to directly connect it to the ongoing debate about FISA in Congress because of the secrecy surrounding the actual activities under discussion (as further obscured by dishonest and misleading Republican and Rockefeller rhetoric), so to try to clarify and to connect some dots, here's my attempt to describe the surveillance scene, using pertinent parts of Kris's savvy research and analysis as highlights and for emphasis, and which others here (Arne, et al) more tech-savvy than me can no doubt help expand upon:

David Kris (emphasis added):

Today, I think the central operational problem in foreign intelligence surveillance is the difficulty of determining, at least in real time, the location of communicating parties who do not wish to be found. This problem stems in large part from changes in telecommunications technology and globalization, including the advent of web-based and other Internet-based communications, mobile communications devices, packetswitched networks, and increased international travel.

[snip]

This operational difficulty gives rise to what I think is the central policy question presented today: when, and under what circumstances and conditions, should the government be allowed to conduct large numbers of national security wiretaps, for long periods of time (more than 72 hours), without individualized findings of probable cause made in advance by judges? Previously, FISA answered that question largely by resort to geographical criteria. As changing technology and globalization nudge those criteria towards obsolescence, we may need to identify a new approach.

He continues:

In theory, therefore, the dispute centers on international communications to or from the United States. In practice, however, it extends further because of the difficulty of determining the location of parties to a communication.

1. "Vacuum cleaner," non-targeted foreign intelligence collection of communications data by our government, including communications retrieved based on watchlist subject-matter keywords or phrases as selectors, rather than based on personal identity selectors, including such communications generated and received by American citizens in America, was never prohibited under FISA so long as the communications were intercepted - if on wire - abroad, or - if in the air (radio and satellite transmissions) - intercepted either at home or abroad (unless the radio waves generated domestically were not intended to be publicly accessible and not intended to reach anyone beyond our borders or unless the radio wave interception was targeting a particular, known individual).

David Kris (emphasis added):

And Congress was told expressly [when FISA was passed in 1978] that watchlist surveillance using subject-matter selectors, such as "terrorism" would not be deemed to target any particular, known U.S. person, even if it inevitably acquired vast numbers of communications made by U.S. persons.

FISA's definition of "electronic surveillance" - which was to define the types of surveillance which would be regulated under the new FISA law - was carefully designed to work around, and thus to exclude from FISA, existing NSA operations which did not directly target Americans. A thorough understanding of the programs, technologies, and operations of the Intelligence Community at that time was obviously necessary and utilized by those drafting FISA to craft this key "electronic surveillance" definition and its silent exceptions. One key Congressional witness put it like this, in 1978 (as quoted by David Kris in his paper):

The types of " surveillance" that would be regulated under [FISA] are rather cleverly defined … to focus on certain purely internal United States communications or on interceptions taking place within the United States. Some types of electronic intelligence gathering would not be covered at all, however, and the Subcommittee should understand that the bill is not all encompassing. For example, if the interception is not physically made in the United States, broad scale monitoring of international radio and cable traffic would be unregulated so long as no particular citizen or resident alien is being targeted. This allows " cleaner" methods of intelligence collection to take place without control. In addition, the interception of purely domestic wire transmissions would not be covered if technology permits the interception to be done outside United States territory – e.g., by surveillance ship off shore or by Satellite.…

These definitions have clearly been crafted to leave many types of intelligence collection activities completely outside the coverage of the bill. - Philip Lacovara in 1978, re the pending FISA legislation

As a result, massive collection has been possible, over years and decades, of the international communications of Americans: if it's data traveling over wire, by being intercepted abroad, and if it's data traveling through the air, by being intercepted both at home and abroad.

The plan in 1978 was to amend FISA at some point to cover, and therefore limit, the American data being intercepted abroad (unless the government could demonstrate probable cause for an individualized warrant from the FISA court), in accordance with our Fourth Amendment. Such amending, however, never came into being.

David Kris:

The Congressional committees were "concerned" about the limits of FISA, found it "desirable to develop legislative controls" over the NSA's signals intelligence activities, and had at least one bill to do so under consideration. But they did not want that broader project to derail the incremental progress represented by FISA.

[And then came the digital age, and this lawless administration and obsequious Congress...]

To be continued...