SOURCE ALERT: U Miami Law Professor Untangles U.S. Supreme Court Ruling in Carpenter v United States


The United States Supreme Court today reversed and remanded the Sixth Circuit's decision in the most consequential case of the term, Carpenter v. United States. The case pitted the right to privacy against the government’s ability to track the movements of its citizens. Carpenter, a convicted robber, argued that using tracking information on his cellphone without a warrant was a violation of his Fourth Amendment rights. Four separate dissents were written in the case that was argued in late November 2017.


An expert in privacy law, Professor A. Michael Froomkin is the founder and editor-in-chief of the online law journal JOTWELL and the founder of the WeRobot conference on legal and policy issues relating to robotics, now in its 8th year.

Why does this matter?

The Supreme Court today said that constitutional law should take account of how intrusive modern technology can be.  So it modified doctrines developed back when we used checks and cops had to tail you to know where you were in light of the fact that we all carry cell phones all the time, and that they constantly report on where you are.  Had it gone the other way the government could track anyone – and get their historical movement records too – with just a simple order, no judge required.

Is this a sweeping decision?

It tries hard not be. On the facts the Court works hard to limit the holding’s reach: the Court says the government needs a warrant for seven days of your cell phone location records.  Other digital records, shorter times, the court does not say, for now.  But the logic of the case says that older, very permissive, doctrines allowing government access to facts about us held by others need to be re-examined in light of new technology. It does not overturn the third party doctrine but rather emphasizes that the doctrine itself should be understood to have limits.

What’s next?

This verdict means we will be back in court often in the coming years to try to find a new balance between law enforcement needs and the needs of a free people not to be surveilled.

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