Can law enforcement legally force someone to unlock a device themselves in the US?

Question

We're all likely aware of the big Apple vs FBI case where the FBI wants to force Apple to open a back door in its encryption on iPhones, and we'll soon discover what the law will decide on that, but it got me thinking:

Obviously a subject could claim that he forgot his password, so that's a dead end, but with fingerprint scanners on new iPhones that leads to a few possibilities. Could the FBI legally do any / all of the following? Why or why not:

• Retrieve fingerprints from a surface the subject makes contact with while in custody to artificially pass the fingerprint scan on an iPhone.

• Force the subject to place his finger on the fingerprint scanner.

Answer 1

Here's what one recent law review article says:

While the privilege against self-incrimination bars compelling communications or testimony, compulsion that makes the suspect the source of physical evidence does not. Given that biometric authentication is merely a scan of physical traits that are compared to previously stored information, one can argue that compelled biometric authentication is not barred by the self-incrimination privilege. Indeed, the Supreme Court has repeatedly held that compelling an accused to demonstrate physical characteristics for identification purposes does not qualify as compelled self-incrimination because it is not testimonial in nature. Likewise, if an accused was compelled to place his finger on his laptop's fingerprint reader, or have his face scanned with his phone's facial recognition software, the physical characteristics would have been used for identification purposes and would likely not be considered "testimonial in nature" such that the scan would violate the self-incrimination privilege.

Erin M. Sales, The "Biometric Revolution": An Erosion of the Fifth Amendment Privilege to Be Free from Self-Incrimination, 69 U. Miami L. Rev. 193, 222 (2014) (citations omitted).