“This was not a breach of national security,” Arthur Ochs Sulzberger, The Times’s president and publisher at the time, said then. “We gave away no national secrets. We didn’t jeopardize any American soldiers or Marines overseas.” (Mr. Sulzberger was himself a Marine who had served in World War II and the Korean War.)

Even though the revelations concerned events that occurred before he took office, President Richard M. Nixon was enraged. He rejected the notion that Americans deserved, almost by definition, to know how their leaders made life-or-death decisions.

Invoking national security, his administration demanded a halt to the papers’ publication. The Times refused, citing the First Amendment. The government then obtained a temporary restraining order from a federal judge in Manhattan. It was the first time in United States history that a court, on national security grounds, had blocked a newspaper in advance from running a specific article — had exercised prior restraint, as it is called.

The case rapidly went to the Supreme Court. On June 30, in a 6-to-3 vote, the justices rejected the administration’s arguments and upheld The Times’s right to publish. There has been no other known instance since then of the government’s seeking in court to prevent an American newspaper from printing secret information by raising a cry of national security, a phrase that Mr. Sulzberger felt was often abused.

“It’s a wonderful way, if you’ve got egg on your face, to prevent anybody from knowing it: Stamp it secret and put it away,” he said.

The Nixon administration certainly tried to put Mr. Ellsberg away. He was accused of, among other things, violating the Espionage Act of 1917. But the case against him and a co-defendant, Anthony J. Russo, fell apart with revelations of serious government misconduct, including illegal wiretapping, and the charges were dismissed.

For Mr. Ellsberg, who turns 86 on April 7, Nixon’s dismissal of the public’s right to know was “a mockery of a democracy.”

“Can you really have democracy, in a real sense,” he said to Retro Report, “with the government having the final voice and the total voice as to what citizens shall know about what they’re doing, and whether they’re telling the truth and whether they’re obeying the law? I would say no.”

Such questions have plainly not faded in this age of WikiLeaks and Edward J. Snowden and their revelations about government monitoring of United States citizens. Admirers often liken Mr. Snowden and the WikiLeaks founder, Julian Assange, to Mr. Ellsberg. These comparisons, however, would seem to stretch only so far. Mr. Ellsberg’s goal was to change a particular government policy. He did not breach secrecy for the sake of breaching secrecy, as latter-day leakers have arguably done.

Then, too, many question whether Mr. Assange is truly committed to transparency or, rather, to finding information that he can weaponize. In the 2016 presidential campaign, he unloaded material intended to damage Hillary Clinton’s candidacy. To more than a few people, it seemed an exercise less in shedding light than in settling scores with a former secretary of state he disliked.

Without leaks, Americans would have known considerably less — or nothing at all — about dubious actions taken in their name. To cite but a few examples: the abuse of detainees at the Abu Ghraib prison in Iraq, the warrantless monitoring of citizens’ emails and phone calls by the National Security Agency, the clandestine sale of weaponry to the Iranian government in what came to be called the Iran-contra affair, and the multi-tentacle Watergate scandal that forced Nixon to resign. More recently, the Panama Papers exposed a global system of tax evasion.

For a nervous bureaucrat, stamping “Secret” on a piece of paper can be a safer course than leaving it untouched and inviting unintended consequences. But more than four million government employees are cleared for access to classified material. This means no shortage of possibilities for Washington to turn into a giant colander.

Despite inherent tensions, a symbiosis between government and the news media has long been evident. Perhaps not surprisingly, and even given the Obama administration’s relatively aggressive stance, instances of leakers’ being hauled into the dock are rare.

And just because something is leaked, it is not necessarily compelling to everyone. Mr. Sulzberger, who died in 2012, attested to that in a speech that he gave in 1996, on the 25th anniversary of the release of the Pentagon Papers. Given that he risked being jailed for publishing them, he felt he should first examine them for himself, he said, but “until I read the Pentagon Papers, I did not know that it was possible to read and sleep at the same time.”

CLYDE HABERMAN, a regular contributor to Retro Report, has been a reporter, columnist and editorial writer for The New York Times, where he spent nearly 13 years based in Tokyo, Rome and Jerusalem. Subscribe to our newsletter here and follow us on Twitter @RetroReport.

This article first appeared in The New York Times.