Until that first term on the Council, Adele Morgan, a childhood friend whom Ms. Palin described in a yearbook inscription as “one of my superest, bestest, funniest cats in Wasilla High,” had never heard her speak of political aspirations.

But years later, as rumors swirled that Ms. Palin might be pondering a run for governor, Ms. Morgan asked whether there was any truth to the talk.

“She said, ‘Yeah, I think that this is really something that I should do,’ ” Ms. Morgan remembered. Ms. Morgan pressed her friend. “Would you ever run for president? I mean, what are you thinking here?”

Ms. Palin smiled her wide smile, then shrugged, Ms. Morgan recalled. “She was, like: ‘Well, I don’t know. We’ll have to see.’ ”