The Digital World Is a Powder Keg. Julian Assange Lit the Fuse.

On the morning of April 5, 2010, a tall, thin man with a shock of silver hair walked up to a lectern at the National Press Club in Washington, D.C. He’d been operating an obscure news website out of Iceland for four years, trying and failing to find a scoop that would set the world on fire. Many of the 40 or so journalists (myself included) who showed up had barely heard of him.

Still, it was hard to ignore his pitch. Three days earlier, we had received an email promising a “previously unseen classified video” with “dramatic proof and new facts.”

But even this bit of hype might have undersold what happened after the man, Julian Assange, pressed play. The nature of proof — the volume and granularity of digital evidence, along with the pathways through which it comes to light — was about to change.

Before, information that leaked from insiders to the public was largely circumscribed by the limitations of paper. In 1969, it had taken Daniel Ellsberg an entire night to surreptitiously photocopy a secret study of the Vietnam War that would become known as the Pentagon Papers.

Now, thousands of such documents — along with images, videos, spreadsheets, email spools, source code and chat logs — could be dragged onto a USB stick and transmitted across the globe in a matter of seconds. Find an insider with enough access or a hacker with enough talent and any security system could be broken. Sources could be obscured. All that was missing was a middleman — a publisher who could find leaks, post the stuff and then take the heat after it went live.

Mr. Assange’s video had an incendiary title, “Collateral Murder.” It began with a still photo of a son holding a picture of his dead father, a driver for the news agency Reuters, followed by leaked footage from a 2007 airstrike showing an American helicopter shooting and killing a Reuters photographer and driver on a street in Baghdad.

There was the drawling voice of a U.S. soldier referring to a man hundreds of feet below — one of the Reuters employees killed in the attack — with an expletive. The video appeared to contradict an account given by a Pentagon spokesman, who had claimed the airstrike was a part of “combat operations against a hostile force.” Within hours, the story had been picked up by Al Jazeera, MSNBC and The New York Times.

What followed was a chain of seismic revelations, some by Mr. Assange’s site, WikiLeaks, some by other outlets. It continues to this day: A trove of State Department cables published by WikiLeaks in conjunction with The Times (2010-11), Edward Snowden’s disclosures from the National Security Agency (2013), the Sony Pictures hack (2014), the Drone Papers (2015), the Panama Papers (2016), hacked emails of the Democratic National Committee (2016), details of U.S. offensive cyberprograms (2017), Hunter Biden’s laptop (2020) and the Facebook Files (2021), to name a few.

Looking back, it’s easy to see Mr. Assange as the father of the digital revolution in leaking. At the time, he was something closer to a talented promoter, one who managed to position himself at the center of several currents that started to converge around the turn of the millennium.

“In the late 1990s and early 2000s, people were hacking into systems and they were taking documents, but those hackers were not ideologically inclined to hack and leak,” said Gabriella Coleman, a professor of anthropology at Harvard whose new book, “Weapons of the Geek,” will include two chapters on the history of hacking and leaking.

Mr. Assange was the first to figure out how to bring its fruits to the big audiences reached by traditional news media. Even as his legal saga reaches its end with his guilty plea and return to Australia, it’s clear that his larger legacy — the volatile fusion of illicit hack-and-leak methods with the reach and credibility of established U.S. publishers — is still unfolding.

On Wednesday, Mr. Assange pleaded guilty to conspiring with one of his sources, Chelsea Manning, to obtain and publish government secrets in violation of the Espionage Act. Ben Wizner, who leads the free speech, privacy and technology project at the American Civil Liberties Union, said the conviction could have far-reaching consequences.

“This was the first time in modern American history where we saw the publication of truthful information criminalized,” said Mr. Wizner. “That it hadn’t happened before was not necessarily because of law. It was probably because of custom. That custom depended on a relationship between the media and the government, an understanding that while they might have different ideas of what the public interest was, they both had a fundamentally American sense of what the public interest was. Then WikiLeaks comes along. Their view is that American imperialism is the greatest threat to world peace. It’s a view of the public interest that is radically different from the U.S. state, and that puts pressure on the old consensus.”

On a rudimentary level, Mr. Assange’s activities largely resembled that of the traditional news media. He was gathering and publishing authentic, newsworthy information. His objectives, however, were different.

Rather than making a claim to neutrality or objectivity, Mr. Assange styled himself as a warrior, sworn to the cause of radical transparency. He refused to accept that even democratic governments required some amount of secrecy to function. Instead, he sought to, in his words, “shift regime behavior” by making secrecy itself untenable. In its place would arise the “people’s will to truth, love and self-realization.”

It was a utopian vision, more of an excuse than an argument. One of thecontradictions of Mr. Assange’s criminal case is how much his freedom depended on precisely the kind of backroom diplomatic dealings that he had spent years working to deride and expose.

As director of national intelligence under President Barack Obama, James R. Clapper Jr. dealt with the aftermath of many hack-and-leak episodes. In an interview over email, he rejected the notion that Mr. Assange’s disclosures had changed anyone’s mind about the morality of the U.S. intelligence apparatus. Instead, he said, WikiLeaks merely served to reinforce the pre-existing views of the faction who already believed that U.S. spy agencies were “evil.”

“I don’t think it moved the needle one way or the other,” he said.

Still, Ms. Coleman said, the history of leaking is still being written, in part by organizations like Distributed Denial of Secrets and XnetLeaks. Like WikiLeaks, these sites solicit and post high-volume digital leaks. But they have higher standards when it comes to redacting information and vetting sources.

As for Mr. Assange, he was “engaging in a very bold experiment,” Ms. Coleman said. “Experiments are bound to have successes and failures. But you needed someone to be bold and go for it.”