1/ Carpenter is coming out in the next week -- maybe tomorrow 10AM -- and I thought I would offer some thoughts on what to look for when the opinion comes out. Argument suggested Ct is likely to say collection of cell site records was a search. But it's the theory that matters.
2/ Some ways to win for Carpenter are narrow, and won't shake the foundation of 4A law very much. Others would be very broad, and would signal a possible rethinking of lots of traditional understandings of the law. It makes a huge difference which the Court chooses.
3/ Probably the narrowest way for Carpenter to win is for the Court to say that location tracking is special -- it's a sort of exception to the traditional 3d party doctrine. I suggested something like that here: lawfareblog.com/best-way-rule-…
4/ Another of the narrower approaches would be to say that disclosing location information doesn't voluntarily convey that information in the 3d party doctrine sense. Depending on the reason the court would offer for that approach, that could be narrow or could be broader.
5/ On the other hand, watch for what the Court says about the third-party doctrine more generally. Will it take on, limit, or reverse cases like Smith v. MD (pen register) or Miller (bank records)? If so, that will be huge news that rewrites enormous swaths of law.
6/ If the Court takes that approach, we'll all be reading the tea leaves of the opinion to get a sense of what the new 4th Amendment framework may look like and how it might apply.
7/ If the Chief is writing the opinion, which seems likely, I would guess based on the argument that Gorsuch will concur. If there are 5 votes in full for the Chief's opinion, Gorusch's view may not have much significance now but may be significant in future efforts to get to 5.
8/ Finally, it will matter whether the Court also tries to answer how reasonableness doctrine applies. If it's a search, is a warrant required or is reasonable suspicion (or something else) sufficient? That could also be a very big ruling, or Court may not reach it. /end
