I can’t remember, but ... isn’t this the second or third case Kagan has not taken part in ?
There have been many in which she was disqualified because she worked on the case as as a Government lawyer.
She must have had an important appointment at the nail salon. She certainly wouldn't recuse herself for anything approaching integrity.
... isn’t this the second or third case Kagan has not taken part in ?
It may not necessarily be because she recused herself. IINM, if a Justice is not present for the oral argument in a given case (for any reason), s/he may not take part (vote) in the decision on that case.