The U.S. Constitution contains provisions that protect us against unreasonable search and seizure (Fourth Amendment) and self-incrimination (Fifth Amendment). These are critically important protections when interacting with police and the larger criminal justice system. Unfortunately, these two rights are almost constantly being challenged in new and novel ways – usually due to advances in technology.

A good example is your cellphone. It contains a treasure trove of personal and private data about you. Should police officers be able to search your phone without your permission in the same way that they might search your pockets? Thankfully, courts are increasingly saying “no.” 

In recent years, courts have ruled that suspects cannot be compelled to unlock their phones by providing an alphanumeric passcode so that police can conduct a search. This, courts have said, would be analogous to being forced to testify against yourself, which violates the Fifth Amendment.

But what about being forced to unlock your phone with a biometric feature like a fingerprint scan, iris scan or facial recognition? In response to the earlier rulings, prosecutors and law enforcement agencies have tried to argue that biometric features are not the same as alphanumeric characters and should be treated differently.

In January, one judge rejected that argument in a landmark decision. She wrote: “If a person cannot be compelled to provide a passcode because it is a testimonial communication, a person cannot be compelled to provide one’s finger, thumb, iris, face, or other biometric feature to unlock that same device.”

This ruling could be overturned until or unless it reaches the U.S. Supreme Court (which it certainly could do). In the meantime, it is encouraging to see that there are judges willing to protect the privacy and Constitutional rights of all Americans.

Cellphone evidence will continue to be a factor in a variety of crimes, from drug sales to identity theft to sexual assault and more. Therefore, it is critical that we set and hold firm boundaries regarding what police are allowed to search and when.