The old saying that “every man’s home is his castle,” while perhaps just a nice adage in my native UK, has a far more important meaning in the United States. Legally, under the Fourth Amendment to the U.S. Constitution, every citizen is protected from the unwarranted search or seizure of their home or property by government officials. Traditionally, this has been a fairly easy legal precedent to follow: no warrant, no entry. Transferring these Fourth Amendment rights from physical to digital property, however, is a little more problematic.

This is because digital property rights remain far less defined than those for physical property. A policeman searching through a briefcase of files without a warrant is clearly in breach of the Fourth, but what if those files were scanned and uploaded to a third-party drive? Does personal information remain private property after being willingly signed over to a social network?

Modern applications of the Fourth Amendment are plagued by outdated understandings and poor definitions of digital property. Modernization is desperately needed if constitutional rights are to be guaranteed in the 21st century.

Back in 2014, for instance, the Supreme Court ruled that unwarranted searches through a person’s cell phone constituted a violation of the Fourth Amendment. This made perfect sense, since reading through someone’s mail without a warrant or permission is no different from reading their texts or emails. So far, so good.

Yet one year later in 2015, the founder of the Darknet marketplace “Silk Road,” Ross Ulbricht, also known by the pseudonym “Dread Pirate Roberts,” was sentenced to life in prison on charges of drug trafficking, “kingpinning,” and other offenses related to his running of the illicit marketplace. Much of the information used in convicting Ulbricht was obtained both without his consent and without a warrant. Why, then, wasn’t this evidence suppressed under the Fourth Amendment? The answer can be found in a legal doctrine from the 1970s.

The “third-party doctrine” affirms that users who provide their information to a third party do not have a reasonable expectation of privacy. Originally, this doctrine was applied to records of telephone calls (though not the actual content of their conversations) in the 1979 case Smith v. Maryland. But it now applies to IP addresses, destinations of messages sent over text or email, and other digital information handed over to Internet service providers (ISPs), as was used in Ulbricht’s case.

Unfortunately, it is this doctrine that is preventing correct application of the Fourth Amendment. Whereas the information voluntarily passed to a telephone company in the 70s only disclosed the origin and destination of a call, the information given to an ISP can reveal far more: the specific websites visited, how much data was transmitted, as well as the locations from which all this was done.

Essentially, this doctrine provides law enforcement with a loophole through the Fourth Amendment. The sheer amount of data uploaded by citizens every day via third-party ISPs theoretically grants police access to a plethora of private information without a warrant.

Ultimately, the third-party doctrine stands as one of the most significant hurdles to Fourth Amendment modernization. Applying it to a telephone conversation may be justifiable: very little information can be gathered from a pen register, aside from who was being called. The same cannot necessarily be said for computers.

More importantly, we provide far more of our information to ISPs and social networks than we ever did to phone companies. While the third-party doctrine may have only given government officials access to a limited amount of information, it now provides a potential backdoor into a wealth of personal data.

Until the third-party doctrine is removed from the American legal system, the Fourth Amendment cannot truly be brought into the 21st century. As interpretations of the Constitution must always adapt to modern life, lawmakers should seriously consider relegating this archaic precedence to history.

Richard Mason is a British freelance journalist.