The United States Supreme Court unanimously ruled this morning that police may not search the cellphones of criminal suspects upon arrest without a separate warrant. This ruling is a huge boost for individual privacy rights advocates.

Some of the decision is excerpted below, and we will update this post with analysis throughout the day.

By a 9-0 vote, the justices said smart phones and other electronic devices were not in the same category as wallets, briefcases, and vehicles — all currently subject to limited initial examination by law enforcement. Generally such searches are permitted if there is “probable cause” that a crime has been committed, to ensure officers’ safety and prevent destruction of evidence.

Chief Justice John Roberts wrote the opinion in Riley v. California and Justice Antonin Scalia agreed with the majority but wrote a concurring opinion.

In the ruling Roberts strongly cited the Fourth Amendment’s protection of an individual rights and the advances of technology that the cellphone represents.

We cannot deny that our decision today will have an impact on the ability of law enforcement to combat crime. Cell phones have become important tools in facilitating coordination and communication among members of criminal enterprises, and can provide valuable incriminating information about dangerous criminals. Privacy comes at a cost.

Our cases have recognized that the Fourth Amendment was the founding generation’s response to the reviled “general warrants” and “writs of assistance” of the colonial era, which allowed British officers to rummage through homes in an unrestrained search for evidence of criminal activity. Opposition to such searches was in fact one of the driving forces behind the Revolution itself. In 1761, the patriot James Otis delivered a speech in Boston denouncing the use of writs of assistance. A young John Adams was there, and he would later write that “[e]very man of a crowded audience appeared to me to go away, as I did, ready to take arms against writs of assistance.” According to Adams, Otis’s speech was “the first scene of the first act of opposition to the arbitrary claims of Great Britain. Then and there the child Independence was born.”

Modern cell phones are not just another technological convenience. With all they contain and all they may reveal, they hold for many Americans “the privacies of life,” Boyd, supra, at 630. 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. Our answer to the question of what police must do before searching a cell phone seized incident to an arrest is accordingly simple— get a warrant.

Interestingly, the Riley opinion goes into great detail about how our modern technology, specifically cellphones, have centralized most all of a person’s life’s information on a cellphone. The Court noted that even after a warrant, the government having one’s cellphone its still because even more information can be discovered later including saved passwords, bank account information, etc.