You know, your smartphone might turn on you. Not due to artificial intelligence or the Rise of the Machines — that’s still science fiction.

It’s because the government says you have no “reasonable expectation of privacy” from your phone’s location data. And the government believes that it should be able to get your location history from your phone provider on, more-or-less, its own say-so.

On Nov. 29, the Supreme Court will review whether the government can get this information without a warrant. The case, Carpenter v. United States, will decide if the Fourth Amendment protects your information.

But the case also raises serious First Amendment issues about the right to free and private association.

Consider what happened during the 1950s when pro-segregation Southern states tried to get the NAACP’s membership list. Those states justified that effort using a range of governmental powers, including corporate registration, legislative investigations, and tax laws. Each time, no matter the excuse, the Supreme Court said no.

In the landmark case of NAACP v. Alabama, the Court noted that “effective advocacy of both public and private points of view, particularly controversial ones, is undeniably enhanced by group association.” It said the First Amendment protects the right “to pursue their lawful private interests privately and to associate freely with others in doing so.”

And so, if the government wanted to seize the member list of the Tea Party, Black Lives Matter or some other group, federal courts could stop it.

So, what does this have to do with smartphones and warrants?

Although all smartphones are telephones, the devices now function like pocket computers. They are our personal assistants, address book, calendar and more. Via social media and other apps, they give us an easy way to — as the old slogan went — “reach out and touch someone.”

Also, as we carry them throughout the day, they enable tracking of our location. As technology advances, your phone company will exactly know where you are every second of every day — and hold onto that data for years.

As Justice Sonia Sotomayor recognized in another Fourth Amendment case, this locational data “generates a precise, comprehensive record of a person’s public movements that reflects a wealth of detail about her familial, political, professional, religious and sexual associations.”

Now imagine if the Supreme Court rules the government can get this information without a warrant. Also imagine that smartphones existed during the fight for civil rights in the 1950s. No doubt Alabama would have asked the cell phone companies to give it this data whenever it wanted.

If the government can get location data of attendance at private gatherings, there’s little need to demand a membership list. Using this data together with other info, governments could reverse-engineer membership and supporter lists. It could even know who attended what meeting. Everyone’s smartphone could become a potential government informant.

If the state can locate the activities of people demanding social change, the NAACP’s First Amendment victory would be destroyed. That vital precedent protects all of us.

The Institute for Free Speech filed a brief in Timothy Carpenter’s case raising these concerns. Two left-leaning racial justice organizations, Color of Change and the Center for Media Justice, joined the brief. So did Americans for Prosperity Foundation and Tea Party Patriots, right-leaning organizations which advocate for limited government. Our brief warned that the “chilling effects from this invasive form of government oversight will do grave damage to the First Amendment.”

You might rarely find these groups in the same room together. But each would like to continue their work without risk of the government turning their supporters’ smartphones against them.

Requiring a warrant as demanded by the Fourth Amendment resolves this problem. It will prevent the government from claiming your smartphone’s location data as an end-run around the First Amendment. Let’s hope the Supreme Court keeps this in mind when deciding this vital case.

This post originally ran in USA Today on November 28th 2017.