I am sorry but you don’t know your history. Mrs Thatcher (as she was then) was derided as minister of education in Ted Heath’s government; “Thatcher the milk snatcher” she was called by the liberal media and the opposition. She later wrot that she learnt an important lesson: “I had incurred the maximum of political odium for the minimum of political benefit.”
There were other times when she wasn’t pitch perfect in interviews; no one is born an expert. Later on, however, when she had developed into a world leader no journalist ever came close to best her.
When Palin was selected by McCain to be his running mate, she had not planned on any sort of national campaign. So naturally, like most other govs, she was not fully prepared for everything. Nobody can know all the details of what’s needed to know unless they’ve had at least a year of practicing for it. She didn’t have that luxury. If she announces for the presidency and cannot answer questions during the debates next year, that’s another matter. I would bet she will have all the answers at the debates.