In a line from the movie referring to Mr. Sulzberger’s bold decision, the fictional stand-ins for the Times editor A. M. Rosenthal and his first wife, Ann Marie Burke, tell Ms. Graham that The Times’s publisher took the risk only after his Washington bureau chief, James B. Reston, threatened to print the Pentagon Papers in the Vineyard Gazette, the small Martha’s Vineyard paper he had bought a couple of years earlier. While Mr. Reston did make that remark, Mr. Goodale told me, “I don’t think anybody took him seriously.”

Mr. Sulzberger, who was known as Punch, published the secret study after reading all of its 7,000 pages. He gave the go-ahead despite his very real assessment that it might land him “20 years to life,” as he put it himself, and over his outside counsel’s refusal to defend the paper if it proceeded.

“Punch was absolutely heroic in publishing the Pentagon Papers,” The Times’s lead reporter on the project, Neil Sheehan, 81, told me in a statement. “He was all alone in making his decision. He had the backing of his senior editors like Abe Rosenthal, who was equally courageous. There was a precedent for Kay Graham. Punch had no precedent.”

The more important lesson is that, in both cases, family-led newspapers placed their journalistic missions ahead of business imperatives. And they did so under intense governmental pressure, a reminder of the important role that principled family leadership plays in the news business.

That has particular resonance in The New York Times Building as Arthur Gregg Sulzberger prepares to take the publisher’s reins from his father, Arthur Ochs Sulzberger Jr., on New Year’s Day, extending the Ochs-Sulzberger family’s stewardship of the paper to a fifth generation.

The idea of steadfast news leadership should matter beyond The Times’s offices, given Mr. Trump’s threats against the tax status of Amazon, the company founded by Jeff Bezos, who bought The Post in 2013, and his denigration of the financial performance of The Times, whose subscriptions and stock price experienced double-digit growth in 2017.

Both media properties have the protection of their owners — a family, in the case of The Times; and a billionaire, in the case of The Post — who are bulwarks against the blind market forces that would have them turn into clickbait-only versions of themselves. The leadership of the Sulzberger family and Mr. Bezos also provides protection against an executive branch that seems all too willing to punish news outlets that don’t adopt the standards of that Trump favorite, “Fox & Friends.”