Commentary on the defense brief in United States v. Jones

In an earlier post, I looked at the petitioners arguments made in the merits brief filed in United States v. Jones, the Fourth Amendment GPS surveillance case. In this post, I wanted to break down the respondents merits brief in the sameway.

I. The four models of Fourth Amendment protection

First, a recap. In a recent article, I argued that the reasonable expectation of privacy test is best understood as four different inquiries. That is, there are four different kinds of arguments that the Supreme Court made about when the government violates a reasonable expectation of privacy and therefore is a Fourth Amendment search. Here are the four models I identified:

(1) the probabilistic model, by which an expectation of privacy is reasonable or not based on how common or expected the governments conduct appears to be;
(2) the private facts model, by which an expectation of privacy is reasonable or not based on the nature of the information disclosed regardless of how it is obtained;
(3) the positive law model, by which an expectation of privacy is reasonable or not based on whether the governments conduct violated some source of law outside the Fourth Amendment; and
(4) the policy model, by which an expectation of privacy is reasonable or not based whether it is desirable to have that outcome as a matter of policy.

Briefs and opinions tend to mix and match the models, making arguments using the model or models that support the argued-for result in that particular context.

II. The defendants merits brief in United States v.Jones

Recall that the investigations in Jones attached a GPS tracking device to the suspects vehicle and tracked the vehicles location on public streets over time. The first question raised by the case is whether the use of the GPS device violated the suspects reasonable expectation of privacy. Much like the governments brief, the defenses brief provides a helpful case study of how arguments based on the four models tend towork.

Heres how the arguments break down. The defendants brief starts by relying on the positive law model. The government action was a search because it infringed upon the defendants property rights, and because the same conduct by a private party would be a tort and (in some states) a crime. Indeed, a few states have barred warrantless GPS surveillance by statute. The fact that the governments conduct violates the principles in those bodies of law outside the Fourth Amendment indicates that the conduct violated a reasonable expectation of privacy. See pages1622.

The brief then turns to the policy model. Warrantless GPS surveillance violates a reasonable expectation of privacy because it is very invasive and easy to do, and letting the government conduct such surveillance without judicial oversight gives the government too much power. See pages 2428. Next the brief turns to the private facts model, and argues that the level of detail in the information that can be obtained from a GPS device makes its use a search. See pages2830.

After responding to the governments brief, Joness brief then returns to the policy model to distinguish the earlier beeper cases on the ground that GPS surveillance raises much more of a dragnet concern than beepers. See pages 3942. The brief then goes back to the private facts model to argue that the net sum of private facts gathered by GPS is very invasive. See pages4345.

(cross posted at Volokh Conspiracy)