Before Wednesday, law enforcement officers could search a person's cell phone right after they were arrested.
Thanks to a U.S. Supreme Court ruling, they will now need a search warrant to do that.
The ruling attaches the fourth amendment - which prohibits unreasonable searches and seizures - to today's technology.
Officers can still take away a cell phone with probable cause, but for some, that's not going far enough to fight crime.
"I understand where they're coming from," Oklahoma County Sheriff John Whetsel said Wednesday, following the ruling. "I don't necessarily have to agree with it because it hampers law enforcement in the field."
Whetsel said in drug trafficking cases, for example, checking a criminal's text messages right away may reveal crimes happening at that time.
Without that ability, "...partners that are committing that crime may continue because you never know about them at that point in time," he said, "or you may never get probably cause in order to look at the phone."
ACLU Oklahoma Executive Director Ryan Kiesel calls the decision a victory for the privacy of Americans because these days, so much of our lives are kept on cell phones.
"The inconvenience to law enforcement here is greatly outweighed by the privacy interests that are being protected," he said.
While the Justice Department argued cell phones are not any different from wallets or purses, Chief Justice Roberts disagreed, saying "...that is like saying a ride on horseback is not materially indistinguishable from a flight to the moon."
Kiesel points out there is an exception to the ruling, if officers fear for their safety or the lives of others.
But in the end, he says needing a warrant to search a phone is no different than needing a warrant to take your diary from your dresser.
"The amount of data that we carry around on our cell phones, the totality of our lives almost, the privacy that we expect from that, doesn't change just because we carry it in our pockets," Kiesel said.
Sheriff Whetsel says it could take up to four hours to get a search warrant for a cell phone.
Kiesel points out today's technology allows officers to retrieve information on a phone even if it's been deleted.