No, the likely reason is that her 1993 speech came out ---you know W has no time for people who deceive him!
Idiotic.
I think W really thought that Miers was a true conservative. He's known her for a while, and she had done good work for him. But I really feel sorry for the person who vetted Miers for the Court. I am pretty confident that the President had no clue about that speech.