Who is Peggy McKinney from The Tears of Autumn and what is their importance?

Peggy McKinney is the wife of the U.S. Ambassador to France, Peggy has always had a high opinion of herself and acts as though she is in charge of the embassy. She and Sybille Webster are alumnae of Sweet Briar. Influenced by the JFK White House, she reads Proust in French, is learning about Africa, and plays left end in touch football every Sunday. She is invited to the Websters for dinner to balance Dennis Foley, on the night of Paul Christopher's return to Paris. With the face of an ingénue, standing like a model, dressing like Jackie Kennedy, she still makes a fool of herself, leading a cheer when word comes of the coup in Saigon and the Ngo brothers' deaths.