The Times article seemed dramatically at odds with one in The Washington Post two days earlier. The Post article quoted McCain advisers as saying that Palin had been thoroughly vetted, including an F.B.I. background check, and that, “Far from being a last-minute tactical move or second choice when better-known alternatives were eliminated, Palin was very much in McCain’s thinking from the beginning of the selection process.”

So was The Times story wrong, as the McCain camp said? It did contain one error. It said that one potentially embarrassing revelation about Palin was her membership for two years in the Alaskan Independence Party, which favors a vote on whether the state should secede. The assertion was based on an announcement by the party’s chairwoman, Lynette Clark, which The Times failed to tell readers. That was a mistake. “We should have attributed it,” Bumiller said. The next day, Clark said she had been wrong. It turns out that Palin’s husband, Todd, had belonged to the party for a time, and she had addressed its annual convention. The Times corrected the error in two follow-up stories.

But the main thrust of its reporting on the vetting process appears to be holding up. The Post said the next day that a lengthy in-person background interview of Palin by the head of McCain’s vetting team did not happen until the day before she was chosen. It also acknowledged that it had been incorrect when it reported that the F.B.I. had checked out Palin. In her home state, the Anchorage Daily News reported that it had found only one person who was asked anything about the governor before McCain selected her. That was the attorney representing her in an investigation of whether she had abused her power in office.

“We stand by our reporting,” said Richard Stevenson, the editor in charge of Times election coverage.

Many readers, like John Southerland of Ocala, Fla., compared The Times’s handling of John Edwards’s extramarital affair and Bristol Palin’s pregnancy and accused the newspaper of a double standard. The newspaper did not seriously pursue the story about Edwards, a populist Democrat, for months, but it put three stories involving Bristol Palin on the first page of its Web site and two on the front page of the printed paper.

I took The Times to task for not trying to report the Edwards story until he acknowledged his affair, but once Edwards came forward, The Times put it on the front page and continued digging. In Palin’s case, the first hint of the daughter’s pregnancy was the family’s announcement of it, and once that happened, it was front-page news everywhere, including the conservative Washington Times. Palin was the anointed Republican vice presidential candidate, and her family was very much part of the biography she was presenting to voters. Two of the New York Times articles were not directly about Bristol Palin: they were about how well McCain researched his choice and about women’s discussions on how Sarah Palin could balance the demands of the vice presidency with the demands of having a pregnant teenager, a baby with Down syndrome and two other children at home.