One theory worth floating is that Palin resigned so quickly and abruptly and self-destructively that she did it in order to appease someone threatening her with exposure of something or other. That would imply we will never know the real reason. I have no clue except that whatever scandal she was facing, she'd have a better go at it as governor. Unless it's so crippling she would have to quit regardless. But since her own explanations makes no sense at all, we are left to wonder. So wonder we shall.