At first glance, the technology used in U.S. v. Forrester seems to accurately map onto the Smith v. Maryland decision, which allowed the use of pen registers without a warrant. After all, just as a pen register records only the phone numbers of incoming and outgoing calls, the to/from addresses of emails was recorded in Forrester. Furthermore, just as the pen register recorded frequency and length of calls, frequency and data volume of emails were both recorded in Forrester. However, whereas this was the extent of the capabilities of the pen register used in Smith, the “mirror port” used in Forrester contained a completely novel function: it revealed the IP addresses of all websites that Alba visited. In fact, recording the IP addresses of visited websites was the primary purpose of the police action in Forrester. Therefore, as the pen register is a partial, but clearly imperfect non-digital analogue for “mirror ports,” the search for the proper analog-world foil begins.
Visiting a website in the electronic world is in many ways analogous to visiting a building in the physical world. Some visits are clearly driven by a certain motive: it would be equally easy to decipher the purpose of a visit to the sporting goods store and a visit to a sporting goods website. On the other hand, some visits are fundamentally ambiguous: whether a visit to a private friend’s house or a visit to the website of extensive supplier of broadly defined goods, such as target.com, the government would have difficulty ascertaining the "content" of the visit without other information. Visiting sites in the electronic world is the equivalent of travelling to establishments in the analog world, and tracking an individual electronically is akin to tracking an individual in the physical world.
Therefore, recording the IP addresses of all electronic sites visited is analogous to placing a GPS device on an individual’s car and recording all places that car goes. Just as a GPS device gives information about the places that have been visited, but not what has gone on in these venues, mirror ports do the same. In this sense, mirror ports do not reveal content. However, they allow for same reasonable inferences to be made regarding the probable activity at the visited sites as are provided by GPS data.
Installing mirror ports is an action comparable to installing both a pen register on an individual’s phone and a GPS device on his or her car. This is not to say that a warrant is necessarily required: lower courts remain divided on this issue with the 7th Circuit ruling in U.S. v. Garcia that the placement of a GPS device does not constitute a search and the Washington State Supreme Court ruling that it required a warrant, in State v. Jackson. However, the limited analogy between mirror ports and pen registers, as employed in U.S. v. Forrester by the 9th Circuit, is clearly lacking and must be reviewed.
Great point, Alex. This is a wonderful deconstruction of the analogy between pen registers and mirror ports. Does it make a difference, in your view, that it may be much easier for the police to ask an ISP to install a mirror port and send them a print-out of the results vs. installing a GPS device on someone's car and monitor the results? Also, does GPS capture as much as IP addresses if the GPS is attached to the suspect's car rather than their person? Knowing where the car goes seems to reveal somewhat less than knowing what webpages the suspect visits. (For example, if the suspect parks downtown and returns an hour later, we don't know where exactly he went). Finally, does it make a difference (at least in terms of subjective expectation of privacy) that the suspect is revealing his web activity only to his ISP, compared with exposing his movements in the real world to the whole world?
ReplyDelete