Thanks to Lyle Denniston, I learned today that the Justice Department has just filed its brief in United States v. Jones, the pending Supreme Court case on whether installing and using a GPS device to detect the location of a suspect’s car without a warrant violates the Fourth Amendment. The DOJ brief is an interesting example of how Fourth Amendment arguments are constructed, so I wanted to blog a bit about it. I’ll start with a bit of context from a recent law review article, and then break down the government’s arguments accordingly. I’ll then make some quick predictions about arguments the Respondent’s brief might make.
I. The Four Models of Fourth Amendment Protection
A few years ago, I wrote a law review article on the “reasonable expectation of privacy” test in Fourth Amendment law: Four Models of Fourth Amendment Protection, 60 Stan. L. Rev. 503 (2007). My argument was that the “reasonable expectation of privacy” test was really four different tests — that there were 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 government’s 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 government’s conduct violated some source of law outside the Fourth Amendment, and
(4) the policy model, by which an