WASHINGTON

Sarah Palin showed on Friday that in one respect at least, she is qualified to be president.

Caribou Barbie is one nutty puppy.

Usually we don’t find that exquisite battiness in our leaders until they’ve been battered by sordid scandals like Watergate (Nixon), gnawing problems like Vietnam (L.B.J.), or scary threats like biological terrorism (Cheney).

When Lyndon Johnson was president, some of his staff began to think of him as “a sick man,” as Bill Moyers told Arthur Schlesinger Jr. Moyers and his fellow Johnson aide Dick Goodwin even began reading up on mental illness  Bill on manic depression and Dick on paranoia.

And so it was, Todd Purdum learned, as he traveled Alaska reporting on Palin for Vanity Fair, that the governor’s erratic and egoistic behavior has been a source of concern for people there.