Important, thoughtful piece: Lawfare: When Does a Carpenter Search Start—and When Does It Stop? by Orin Kerr:
The Supreme Court’s recent decision in Carpenter v. United States raises lots of fascinating and novel Fourth Amendment questions. In this post I want to focus on one interesting and important set of questions: When does a Carpenter search start, and when does it stop? I don’t have a lot of answers, but I think the questions are important to consider. This post will explore the questions and will end with a set of hypotheticals that I think are worth pondering.
This is a long post, so here is a roadmap. I’ll begin by explaining why the timing of Fourth Amendment searches was pretty easy before Carpenter, and I’ll turn next to why Carpenter complicates the issue. I’ll then discuss the stages of surveillance and explain why the timing of Carpenter searches is pretty important. After briefly covering the timing of searches suggested by the Jones concurrences, the next section goes through the language of Carpenter and argues that the opinion leaves the timing questions pretty open. I’ll end with four hypotheticals designed to bring out different ways of thinking about when Carpenter searches start and stop.