The US press had long prided itself on investigating the secret doings of government. On occasion, the media honored government requests to hold back details or delay publication of a story if persuaded that disclosure would endanger a US operation or American lives. But journalists took seriously their role as watchdogs—and considered few institutions more important to watch than US intelligence agencies.

The Washington Post held an exalted position in the universe of watchdog media dating back to the days of Watergate, when its investigation resulted in the 1974 resignation of President Richard Nixon. Over the following decades, it fielded numerous sensitive national security stories, and as a rule published them after notifying the target institution of its intention to do so. Granted, there remained a tension between the public’s right to know about national security operations, and the government’s insistence that secrecy contributed to success and saved lives. The Post considered each case on the merits.

In June 2013, the Post found itself again with a story that had wide-ranging national security implications. Longtime national security reporter (and Pulitzer Prize winner) Barton Gellman, while no longer on staff, had brought the Post a dramatic story of widespread US government surveillance of “foreign communications” which incidentally had swept up millions of messages from private US citizens. Gellman had been working periodically since February, in collaboration with documentary filmmaker Laura Poitras, to check out whether their source—who continued to remain anonymous—was credible. They had never met, never talked on a telephone.

The source—who called him/herself Verax—had a classified document that demonstrated how, for a period of years, the National Security Agency (NSA) had been given access to the servers of nine major US Internet companies, and had secretly reviewed millions of communications. The targeted surveillance program, codenamed PRISM, had captured emails, texts, photos and documents of suspect individuals on an unprecedented scale and unbeknownst to the public or to most members of Congress. Over months of encrypted electronic conversations, Gellman had determined to the extent possible that Verax’s information checked out.

By early June, Post Executive Editor Martin Baron and the newspaper’s legal team were prepared to publish the story. Gellman, per the Post’s custom, had notified the White House about the story and an official—after first asking that the article be killed—had requested that at least the Post not publish the names of the companies, on the grounds that publication would destroy the arrangement and hence threaten national security. As the Post debated its options, on Wednesday, June 5, the British Guardian newspaper published a story about Verizon (not one of the nine) collecting telephone records for the NSA. Gellman knew that the Guardian story was based on documents from the same source; it was only a matter of time before the Guardian had the PRISM story as well.

Gellman and the Post had a decision to make. Each Internet company vehemently denied knowledge of the PRISM program. The public might well react with outrage to the revelations, with severe economic consequences for the firms. The White House, meanwhile, was adamant that the names be withheld to preserve the program. The competitive pressure to publish was intense, but Gellman had to ask himself what the identities added to the story. Did the public’s right to know include names? He had to draw on his wide experience reporting on national security matters to decide: identify the companies or not?