Also noteworthy is the fact that the agent draws a distinction between mobile phones and computers: the warrant explicitly notes that it does not apply to computers in the apartment and that they will not seize or search any computers they find.
From a law enforcement point of view, this makes no sense to me. Why not try fingerprint unlock on the computers too. A modern mobile is substantially just a small form factor computer anyway.
The Supreme Judicial Court rejected the argument that doing so would violate the Fifth Amendment against self-incrimination and said that the government only had to prove that someone knew their passcode. The legal argument was that the contents on the phone already exist and so someone isn't incriminating themselves because they aren't providing any new information.
This also makes no sense to me. The information may not be originated when I'm compelled to unlock my phone, but your access to it is. Much the same as being able to "take the fifth" when questioned; the information already exists in my head, I'm just denying you access to it because it doesn't help my legal situation.
she also warned "the court’s decision today sounds the death knell for a constitutional protection against compelled self incrimination in the digital age."
Yes, yes it does.
"After today’s decision, before the government may order an individual to provide it with unencrypted access to a trove of potential incriminating and highly personal data on an electronic device, all that the government must demonstrate is that the accused knows the device's passcode."
Of course they know the passcode to their phone. Why would it be otherwise? In much the same way though, they know what they were doing, with whom and where a week ago Friday at 9pm, but that data seemingly cannot be compelled from them, and I'm far from clear the circumstances or outcome differ substantially.
In Virginia, the current legal default is that someone cannot be forced to hand over their passcode precisely because to do so would break the Fifth Amendment. But the authorities can use fingerprints to unlock a phone because a fingerprint is a "non-testimonial physical characteristic."
That seems weak to me. What is the purpose of the fifth amendment? If it is to grant you the right not to incriminate yourself, then why does that right stop where the electrons begin? Gaining access to my information I would not choose to divulge because it would incriminate me seems to me to be fundamentally the same whether you ask politely, use a rubber hose, or use my fingerprints against my clear expressed wishes.