OK, she was the Governor of Alaska...that in itself represents credibility to me. Being a state Governor is a big job...like being a CEO of a big company. Lots of responsibility, decisions, and dealing with a huge variety of issues and people. And being held to account for bottom line results. I understand Alaska didn't suffer too badly under her governorship, so I'm thinking that she might have done a pretty good job of it. Again, some credibility there.
And, being a good CEO (my opinion), she was likely following a good strategy of any good CEO which is to not divulge everything you're going to do until you've done it. We don't know what she had in mind when she resigned without notice, but I'd bet it's part of a bigger plan. Which she chose not to tell the mainstream media about. Which - once again - would demonstrate a pretty good ability to think "strategically" on her part. Adn that would be a very good strength in a future President of the USA.
Just my opinion, of course. ;-)
If she did such a good job as Gov, I wonder why it was that Alaskans took her resignation with nary a peep of protest, and probably (my opinion) huge sighs of relief. She may have put Alaska on the map for many Americans in the lower 48, but were I an Alaskan, I would surely not be applauding the way she did so.