Yes. Kirsten Gillibrand (right).
Never heard of her? Shame on you. (Mind you, nor had I)
Caroline Kennedy's last minute withdrawal from the replacement stakes is reported to have involved tax and personal problems.
My own take is that Kennedy did not deserve to be a Senator at this stage because, quite frankly, she was useless. You only have to count the number of "ya knows" in the interview below to realise that.