“Unfortunately, there are issues with undesirable images within the data,” a document from Britain’s General Communications Headquarters, a spying agency, says about its interception of citizens’ private webcams. “It would appear that a surprising number of people use webcam conversations to show intimate parts of their body to the other person.” Before getting distracted by the question of whether that is, in fact, surprising, one has to ask: What other private things do the G.C.H.Q. and the N.S.A. show each other?

The Guardian got the documents about webcam interception by way of Edward Snowden, whose leaks have been an education. This set shows that the G.C.H.Q. collected Yahoo-webcam exchanges as they were sent. (Yahoo has said that it didn’t know about this and that it’s angry; the G.C.H.Q. was apparently also interested in tapping into Microsoft’s Kinect.) It did so indiscriminately—taking everything it could, whether or not there was any reason to suspect the person involved. The term of art is that the data was “unselected.” The problem as the spies saw it was that they had too much data—they dealt with this not by narrowing their scope but, instead, by taking every fifth frame. The program was called Optic Nerve, and, although it operated under the G.C.H.Q. rubric, the N.S.A. appears to have been an inseparable part of it. As the Guardian reported,

Optic Nerve was based on collecting information from GCHQ’s huge network of internet cable taps, which was then processed and fed into systems provided by the N.S.A. Webcam information was fed into NSA’s XKeyscore search tool, and N.S.A. research was used to build the tool which identified Yahoo’s webcam traffic.

Do the G.C.H.Q.’s cable taps touch on the webcam conversations of Americans? They certainly could. And, given the amount of help the British agency received, this almost looks like an American project. The N.S.A. is not supposed to spy on Americans without a warrant. There are qualifications to that, every one of which the N.S.A. seems to have taken to its illogical extreme. We have already learned—again via Snowden—that the N.S.A. considers every American’s telephone records “relevant” to its foreign-surveillance mission, and believes that it can look closely at the communications of anyone who has been in touch with a person who’s been in touch with a person whose been in touch with another person the agency thinks is a suspicious foreigner. That’s called not targeting the person you’re spying on. But there may be times when the N.S.A. considers it easier to have foreigners spy on Americans and then get the information that is collected, however private it may be.

There is a structure for this: the “Five Eyes,” the sharing of intelligence between the United States, the United Kingdom, Canada, Australia, and New Zealand. This has been going on since the Second World War, and there is nothing wrong with it, in principle. What’s troubling is the sense that the agencies are trading loopholes rather than actionable intelligence: you can’t do this but I can, so let’s each do the other’s forbidden thing and then talk about it. That’s not the idea behind the legal and constitutional restrictions on the N.S.A.

The G.C.H.Q. now has plenty of webcam footage to trade. But a lot of it—between 3.4 and 10.8 per cent, according to the G.C.H.Q.’s estimate—“contained undesirable nudity.” Analysts could search broadly in the metadata associated with the images, but were only supposed to look at pictures when they thought there was a reason to—although in practice this meant that they could also, according to a document the Guardian cited, look at “webcam images associated with similar Yahoo identifiers to your known target.” (Anyone with a common name who has tried to pick a username and found that the first dozen obvious variations were already taken has a sense of how broad that could get.) Webcams don't only see you; they might also get the books on the shelf behind you, or the political poster, or the person who came to visit. The G.C.H.Q. had also hoped to use a wide assemblage of people’s private pictures to fine-tune its facial-recognition software. But the algorithms got confused by images that showed too much skin from parts of the body that weren’t faces.

“Undesirable” is a funny word to use to describe intimate exchanges one intrusively collects. One doesn’t have to have sympathy for webcam porn to find the G.C.H.Q.’s complaints about it annoyingly whiny. There is a worry, in the documents, that the spies might be offended by what they see, as if a naked public has uncharitably created a hostile work environment for intelligence analysts. (“Users who may feel uncomfortable about such material are advised not to open them.”) Is it clothes that appear to be thrown off too quickly, because of the every-fifth-frame jumpiness, or in a graceless manner, that made the images “undesirable”? People don’t forfeit privacy because they have undesirable political views, and certainly not if they happen to tilt their webcams in angles that are less than helpful for surveillance agencies’ facial-recognition software. If our governments find our bodies so awkward, they can just stop looking.

An aerial view of Britain’s General Communications Headquarters in Cheltenham, Gloucestershire. Photograph: UK Ministry of Defense.