In the Whitewater case, she worked to deflect a Senate subpoena for notes of meetings between the White House and private lawyers. She solicited supportive statements or op-ed articles from former officials and law professors, even ghostwriting or editing some of them.
I don’t this reflects badly on Kagan; her job was to defend Clinton. But I’d be very curious to know which law professors, if any, thought it was appropriate to sign their name to a piece ghostwritten by a member of the Clinton administration, defending Clinton.