I believe that to be the case. She has to know that by campaigning for McCain (in a lousy PRIMARY, of all things), she loses her reputation as someone who will courageously take on her own party's corrupt establishment, and that is a selling point she can not afford to be without.
Mr. niteowl77
I think Rusty Humphries and Dough Hayworth summed it up best by saying that they understand Sarah’s loyalty, and they expect and welcome her endorsement of Hayworth after McCain loses.