Fallows' overarching point is that Palin simply hasn't been interested in foreign policy:
What Sarah Palin revealed is that she has not been interested enough in world affairs to become minimally conversant with the issues. Many people in our great land might have difficulty defining the "Bush Doctrine" exactly. But not to recognize the name, as obviously was the case for Palin, indicates not a failure of last-minute cramming but a lack of attention to any foreign-policy discussion whatsoever in the last seven years.
The most compelling thing here is that Fallows isn't attacking her intelligence, competence, patriotism or enthusiasm for the job. He's stating the obvious. Anyone who has paid any attention to foreign affairs for the last seven years would have been able to identify, if not aptly define, the Bush Doctrine. Palin's blank look and defensiveness, particularly her apparent wish to make Gibson into the bad guy, tell everything necessary.
And the rush of words, oy, she's like one of my high school juniors (not the AP group) answering an essay question on a story she never even heard of let alone read.