A little bit of errant security information made its way into the Supreme Court’s oral argument in U.S. v. Jones this week. Justices Ginsburg, Kagan, and Breyer were testing the fairly narrow limits of the position advocated by Jones’ counsel. He focused on invasion of Jones’ “possessory interest” in his car when the government placed a GPS device on it.

If the Court were to find that attachment of a device invaded Jones’ Fourth Amendment interests, this wouldn’t protect him from a system of cameras that developed much the same information, noted Justice Ginsburg. Justice Kagan continued:

What is the difference really? I’m told — maybe this is wrong, but I’m told that if somebody goes to London, almost every place that person goes there is a camera taking pictures, so that the police can put together snapshots of where everybody is all the time. So why is this different from that.

Justice Breyer continued down this line:

And in fact, those cameras in London actually enabled them, if you watched them, I got the impression, to track the bomber who was going to blow up the airport in Glasgow and to stop him before he did. So there are many people who will say that that kind of surveillance is worthwhile, and there are others like you who will say, no, that’s a bad thing.

I’ve spent a lot of time examining terrorism incidents, and the scenario described by Justice Breyer does not sound familiar to me. There was an attack on the Glasgow airport in 2007. That attack was a qualified success—heavily qualified: one of the attackers incinerated himself in the course of causing minor injuries to a few standers-by and only modestly damaging the airport. I’ve found no report that surveillance cameras were involved in monitoring or apprehending the attackers—much less stopping the attack—or in stopping any similar-sounding attack.

Security cameras and surveillance generally are over-rated as preventives of crime and terrorism. They are some help in discovering information about crime after the fact. No help is needed when a major incident turns the eyes of an entire city or nation toward discovering what happened.

I doubt that the case will turn on Justice Breyer’s apparent error, but it clearly influences his thinking, and he shared it with other members of the Court. The people he counts as saying surveillance is worthwhile do not have prevention of an airport bombing in Glasgow to back them up.