The Supreme Court has ruled unanimously that a warrant is required in order to search the cellphones of the people they arrest.

As the New York Times reported, the impact of this decision is very broad, as it almost certainly also applies to searches of tablets and laptop computers, and possibly even searches of homes and businesses and of information held by third parties like phone companies.

Speaking for the Supreme Court, Chief Justice John G. Roberts, Jr. noted, “[Cellphones are] such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.”

Chief Justice Roberts also provided some background into the intertwined nature of the freedom against unreasonable search and seizures and the birth of the United States. “One of the driving forces behind the American Revolution was a revulsion against general warrants that allowed British officers to rummage through homes in an unrestrained search for evidence of criminal activity. The fact that technology now allows an individual to carry such information in his hand does not make the information any less worthy of the protection for which the founders fought.”

Prior to this decision, police officers relied on principles that exempted them from first obtaining a warrant, namely the search incident to lawful arrest exception. This exception states that an officer may search those items that are in the immediate control of the arrestee in order to ensure officer safety and preserve evidence.

Chief Justice Roberts said neither of these reasons for applying the search incident to lawful arrest exception made sense in the context of cellphones. “While the police may examine a cellphone to see if it contains, say, a razor blade, once an officer has secured a phone and eliminated any potential physical threats, however, data on the phone can endanger no one.” Furthermore, he commented that the possibility of remotely destroying data on a phone that may qualify as evidence is highly unlikely since the police may either turn the phone off, remove its battery, or place it in a bag made of aluminum foil.

Nonetheless, one exception to the warrant requirement still remains. “Should the police confront an authentic ‘now or never’ situation, they may well be entitled to search a cellphone under the exigent circumstances exception, which requires an emergency-type situation that must be justified in light of all surrounding circumstances.