Her motive might not be political. It might be personal. As in she waited until the most important moment of his life to **** him over.
Well, she stated in her testimony that she reached out to Anna Eshoo's office when she saw Kavanaugh was on a short list of nominees to the SC. She was trying to alert Diane Feinstein through Eshoo's office in order to speak out against his nomination. That's not to say it's wrong, but the timing of her accusation coincided with his being nominated. She could have brought this up a long time ago when he was appointed to the Court of Appeals in DC. But for some reason, the SC nomination was what motivated her.