She took it seriously enough to complete a second round of questions.  So whether this was really her decision is debatable.  Her letter suggests she believed she could pass the Senate.  Bush could have continued to support her, adding that the Senate knows they can't have materials of the Executive Branch.  Frankly, what makes more sense is that he doesn't need two major fights right now, and the indictments which are apparently coming are going to really affect the Administration's popularity.   Maybe he's picking his battles.  I think he probably told he would not oppose her withdrawl.  I think if she was really loyal she would have refused the nomination to begin with.  She knows she's not qualified more than anyone.  Picking her was about as qualified a choice as picking his secretary for neither knows all that much about the Constitution.