If you wanted a counterterrorism technology that could match Amtrak in terms of derailments, you couldn’t do much better than to use “stand-off explosive detection technology” in the transportation environment. Sen. Chuck Schumer (D-NY) has been touting its testing and potential regular use in New York.
The surface appeal of a technology that can reveal hidden items is obvious, especially in New York, where a poorly outfitted would-be suicide bomber recently injured himself with a device strapped to his mid-section. But the actual use of a technology to look under people’s clothes would cost more in dollars and privacy than it would provide in security benefit.
There is no doubt that stopping a suicide bomber is valuable. So in myriad ways New York’s transportation systems, the city of New York, the state, and the people of this nation as a whole have a lot of systems in place to do that. Just consider how often a suicide bombing occurs in our huge, populous country. Very rarely indeed. Should we spend taxpayer dollars on technology and manpower to drive this very low risk down a bit more?
It’s charitable to call the technology “stand-off explosive detection,” because it merely detects objects. The human body naturally gives off electromagnetic radiation, and this machine detects anomalies on bodies indicated by the blockage of that radiation. It interprets certain of those anomalies as potential bombs, and the idea is that police or other security agents would scramble to interdict each person with a deviant electromagnetic profile.
Now, consider how such a technology would intersect with transportation, an environment in which people carry lots of things. The detectors would almost always send law enforcement personnel after people with colostomy bags, money belts, the SCOTTeVest, and any number of things shoved in their belts and brassieres to free up their hands for luggage and purses.
No doubt, the designers of the technology think they can tune the technology to the radio-interference profile of explosive vests and such. Happily, they have very little experience to go on. The potential configurations of explosives devices are many. That means “stand-off explosive detection technology” will have an almost 100% false positive rate. It is a data mining operation with all the defects of personal information data mining for terrorism detection. It will use expensive machines to burn up the time of law enforcement personnel by sending them after innocent travelers (who are already quite harried enough).
But the kicker is constitutional. The Supreme Court has already ruled that this kind of technology is a Fourth Amendment search. In Kyllo v. United States, the Court found that using “a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion,” is a “search,” and is therefore “presumptively unreasonable without a warrant.” This is the same kind of technology as the thermal imaging machine in Kyllo. It just operates in a different band of the electromagnetic spectrum, and it would be used on “persons” rather than “houses.” Both are on the list of items specifically protected by the Fourth Amendment.
There is a thread of Fourth Amendment law suggesting that searches aimed only at contraband are not searches, but the stack of doctrines on which that idea rests is tottering. In recent Fourth Amendment cases such as Carpenter, we’ve been arguing that the Supreme Court should drop all the doctrine and recognize searches as searches. Kyllo is the leading 2001 case where the court did exactly that.
Good politics in New York? You bet. A way for the Department of Homeland Security to burn up more budget authority and taxpayer dollars? Oh, yeah. But in terms of actual policy? The idea of cost-effectively making Americans safer? This technology is pretty much guaranteed to careen off the tracks.