The Fourth Amendment protects us from unreasonable government searches and seizures. In practical terms, this means that law enforcement has to get a warrant — demonstrating to a judge that it has probable cause to believe it will find evidence of a crime — in order to search a place or seize an item.
In deciding whether the Fourth Amendment applies, courts always look to see whether people have both a subjective expectation of privacy in the place to be searched, and whether society would recognize that expectation of privacy as reasonable. The Supreme Court made this point clear in a landmark 1967 case, Katz v. United States, when it ruled that a warrantless wiretap of a public payphone violated the Fourth Amendment.
The Third Party Doctrine, or How the Supreme Court Got Us Into This Mess
In 1979, the Supreme Court created a crack in our Fourth Amendment protections. In Smith v. Maryland, the Court ruled that the Fourth Amendment didn’t protect the privacy of the numbers we dialed on our phones because we had voluntarily shared those numbers with the phone company when we dialed them. This principle — known as the Third Party Doctrine — basically suggests that when we share data with a communications service provider like a telephone company or an email provider, we know our data is being handed to someone else and so we can’t reasonably expect it to be private anymore.
The government took this small opening created by Smith v. Maryland and blew it wide open. It argued that this narrow 1979 decision about phone dialing applied to the vast amount of data we now share with online service providers — everything from email to cell phone location records to social media. This is bogus and dangerous.
When we hand an email message to Gmail to deliver on our behalf, we do so with an intention that our private communications will be respected and kept in strict confidence, and that no human being or computer will review the message other than the intended recipient. But the government argues that because we handed our communications to a service provider, the Fourth Amendment doesn’t require them to get a warrant before snooping around our inbox.
Luckily, the courts are beginning to agree with us. In a leading case where EFF participated as amicus, United States v. Warshak, the Sixth Circuit Court of Appeals agreed with us that people had a reasonable expectation of privacy in their email, even if it is stored with a service provider, and therefore the government needed a search warrant to access it. And in the recent Supreme Court case, United States v. Jones, Justice Sotomayor said that she thought the Third Party Doctrine was outdated, while she and four other Justices — including Justice Alito — raised concerns about the information gathered by our cellphones.