Still, strange as this list may have seemed to producer Mapes and Dan Rather—a scene in “Truth” shows them rolling their eyes as Mr. Burkett recites his alleged real sources for the documents—both Mr. Rather and Ms. Mapes would go on to assert their undeviating belief in the truth of those documents.

Mary Mapes after all had been thinking about Mr. Bush’s National Guard service since 1999. She had been interviewing, waiting, five long years to tell the world about her suspicions that George W. Bush received special treatment to avoid going to Vietnam.

Five years. What this says about the special zeal that drove this mission we can leave aside. Ms. Mapes would find her fateful opportunity, finally, with Mr. Burkett and his documents. To obtain them, she complied with Mr. Burkett’s special request that she connect him with the Kerry campaign so that he could provide advice on election strategy. Ms. Mapes promptly called Mr. Kerry’s top aide, Joe Lockhart, telling him about the important, unfriendly investigative story on George W. Bush that CBS was about to run, and about one of her chief sources, who could be of interest to the Kerry campaign—they might want to call him.

In the years since this affair, Mr. Rather and Ms. Mapes have held fast to their regularly repeated assertions that whatever mistakes may have been made, they had reported a true story. “Truth”—starring Cate Blanchett as Mary Mapes facing down the enemies of the good and the true—is the latest iteration of the Mapes-Rather claim that the validity of their story wasn’t compromised merely because the supporting testimony was fabricated.