Thread by @OrinKerr

First Circuit held en banc argument today in US v. Moore-Bush, on the 4th Amendment limits of pole cameras (if any) after Carpenter v. US.

Listen to the 1:47 hours of oral argument here:
media.ca1.uscourts.gov/files/audio/19…

News report here: courthousenews.com/a-police-camer…

h/t: @howappealing

I don't have a clear view of how Carp should apply to pole cameras -- hard Q, I think -- but I thought DOJ's arg should have been simpler than it was. Best arg for DOJ, I think, is "Carpenter is about an REP in the whole of a person's movements, and a pole camera doesn't move."

From the govt's perspective, that's your limiting principle in a pole camera case, I think: Carpenter is only about the whole of movements, and it doesn't apply to a camera fixed on one place. (May or may not persuade a particular court, but I think it's the govt's best arg.)

So wild that there are only 5 active judges on the CA, with one vacancy for President Biden to fill. That's a really small court. By comparison, the CA9 has 2,391 judges, much larger (I kid, I kid, only 29).

At 35 minutes, defense counsel is pushed by Judge Lynch, and argues for the mosaic theory -- a small amount of pole camera use would have not been a search. Lynch and Thompson ask, where's the line that triggers the search?

Defense counsel proposes that the standard is a nosy neighbor or onlooker test, which could be turned into a one-day rule: You can use a pole camera for a day without a warrant. (This raises endless impossible Qs, I I think, as I have argued here: repository.law.umich.edu/mlr/vol111/iss… )

I think that's more or less what you argue if you're representing this particular defendant, as you get nothing from arguing for a broader rule; argue for a narrow rule that helps your client and let the judges pull out their hair over whether they can make it work (they can't.)

At the 1:00 mark, counsel for the co-defendant argues for the broader rule rejecting the mosaic theory: Any pole camera monitoring is a search. You can't say a small amount of surveillance is okay.

ACLU, arguing as amici for mosaic theory at 1:13, is asked where the line is. First responds that the Court shouldn’t draw one. Second argues, if there has to be a legal standard, the test should be based on the practical abilities of police and public.

Questions follow, what exactly are the realistic expectations people have of whether they’re being monitored and how much?

(That’s one of the oddities of Carpenter: people have an REP in CSLI as a matter of law because they no longer have an REP in that info as a matter of fact. It was equilibrium-adjustment: law giving what new technological facts gave away.)

At 1:26, ACLU's proposed rule would keep the law really vague: Argues court should adopt rule that govt needs a warrant for "long term" surveillance directed at the curtilage, but proposes that the court should not try to say what "long-term" means.

It's interesting, the mosaic theory is now 9 years old, and its proponents are no closer to explaining what it means today than they were in 2012. With any luck, maybe we'll know by 2030? Or at least 2040.