It was only in February, with the overwhelming negative public reaction to those disclosures, that Mr. Murdoch and his son with whom he runs the company, Lachlan Murdoch, began seriously considering settling. Yet they made no major attempt to do so until the eve of the trial in April, after still more damaging public disclosures.

At the center of the action was Mr. Dinh and his overly rosy scenario.

Mr. Dinh declined several requests for comment, and the company declined to respond to questions about his performance or his legal decisions. “Discussions of specific legal strategy are privileged and confidential,” a company representative said in a statement.

Defenders of Mr. Dinh, a high-level Justice Department official under President George W. Bush, say his initial position was sound. Because of the strength of American free speech protections, Dominion needed to clear a high bar. And unfavorable rulings from the Delaware judge who oversaw the case hurt Fox’s chances, they argue.

“I think Viet and Fox carried out just the right strategy by moving down two paths simultaneously — first, mounting a strong legal defense, one that I think would have eventually won at the appellate stage, and, second, continuously assessing settlement opportunities at every stage,” said William P. Barr, the former attorney general under Mr. Trump who worked with Mr. Dinh earlier in his career.

Of course, the case would have been difficult for any lawyer. As the internal records showed, executives knew conspiracy theories about Dominion were false yet did not stop hosts and guests from airing them.