Barton Gellman: ‘The Assange precedent is dangerous’

Barton Gellman is an investigative journalist celebrated for his reports on 9/11, former US vice-president Dick Cheney and the surveillance state. He was the only mainstream journalist that Edward Snowden approached in 2013 to publish his revelations about far-ranging cyber surveillance by the US National Security Agency. His new book, Dark Mirror, is an account of his interactions with Snowden and the struggle to expose the US government’s assault on privacy.

The spectrum of opinion on Edward Snowden runs from heroic whistleblower to shameless traitor. What’s your own understanding of the man?
Those labels seem to me like cartoons. I see him as being quite sincere in his beliefs. I think he was motivated more or less exactly as he described. He has a very black and white sense of right and wrong. I described him in the book as sharing certain elements with other self-described whistleblowers: zealotry and certitude of their own beliefs. But I believe his ultimate choices were heartfelt. My own view is that he did more good than harm.

What was the greatest contravention of privacy exposed by the Snowden files?
One that made its way most clearly into public consciousness was the universal collection of telephone-call records of Americans. That had to do with who you called, when you talked to them and so forth, the so-called metadata, not the content of the telephone calls. In my own mind, the greater problem is the practice of bulk surveillance of content.

When you were first approached by Snowden, were you most worried about whether you could stand the story up, or if it would lead you to prison?
The idea of prison, of criminal penalties was hypothetical and distant in my mind, because it’s unprecedented. The lawyers warned that it was possible in this case, but it wasn’t my primary concern at all. My primary concern was doing justice to the story and not doing inadvertent harm. And equally, protecting myself and the materials. I was worried about the American government trying to seize my notes and documents. I was worried about foreign hackers. I was worried about external intelligence services and I had reason, it turned out, to worry about all of them.

Is it difficult in those circumstances to know the difference between taking wise precautions and paranoia?
Well I don’t want to say it was gratifying that my paranoia was rewarded with evidence. But I did discover that there were indeed foreign intelligence services trying to break into my accounts, that I was, in fact, being hacked, that the US government was considering staging a raid to seize my notes and documents. And so the paranoia was grounded in real-world experience.

The so-called mainstream media is much criticised these days, but do you think Dark Mirror is a defence of the traditional media and its methods?
I try to give an honest and granular inside view of investigative journalism as it happens in real time, to show the kinds of steps we take to take care that we have a story right, that we consider all the implications, that in the case of national security we consider also the harms as well as the benefits to publication. And it’s more a show than a tell. I’m not trying to moralise about how it ought to be done. I’m showing how it was done. In that sense, I suppose, it is a defence of evidence.

You write that the crimes alleged against Julian Assange are “very hard to distinguish from what I did with Snowden’s NSA archive”. Are you worried about the possibility of future prosecution?
I am very much worried that the precedent that the present US administration is trying to set with Assange is dangerous, and quite new in the American legal tradition. Assange is charged with asking for information, with receiving information, and with publishing information. And I don’t mind saying that those are exactly the things that I do. And there has never been a prosecution for espionage based entirely on publication. If that’s allowed to stand, there’s absolutely no reason why it couldn’t be used against the Washington Post or the New York Times or CNN.

What books are currently on your bedside table?
I’m reading a very good forthcoming book called Baseless by Nicholson Baker. It’s about his entertaining and relatively fruitless journey through the Freedom of Information Act in America in an effort to get at secrets about non-conventional warfare in the 1940s, 50s and 60s. It’s a wonderful diary of futility and its consequences. And I’m actually planning to reread George Packer’s Our Man, a life of Richard Holbrooke, to try to work out how he managed it. It’s an extraordinary biography.

What is the last truly great book that you read?
American War by Omar El Akkad stands out. It tells the tale of a second US civil war brought on by climate change, half a century hence, with a multigenerational narrative that feels like genuine history. Horrifying, deeply convincing, with enough notes of redemption to satisfy. I’d also like to put a word in for Any Human Heart by William Boyd, a modern classic that I discovered only recently.

What book might people be surprised to see on your bookshelves?
I’m a great fan of detective fiction and speculative fiction, so I recently made my way through a nostalgia tour of Rex Stout and his Nero Wolfe mysteries. And I’m a great fan of NK Jemisin in the world of science fiction and fantasy.

Which author do you always return to?
I think Rex Stout and Larry Niven.

Which book would you give to a young person?
I might suggest Lord of the Flies, for a chance to ruminate early about human nature.

In the Dutch historian Rutger Bregman’s new book, Humankind, he challenges the ideas in Golding’s book and finds an example of shipwrecked boys who behaved very differently, in a much more mutually supportive fashion.
I take the novel as a starting point for discussion to see whether a young reader really believes that’s the way people behave and what are the alternative approaches. My view of human nature is not nearly as dark.

• Dark Mirror by Barton Gellman is published by Vintage (£25). To order a copy go to guardianbookshop.com. Free UK p&p over £15