Who is Dennis Foley from The Tears of Autumn and what is their importance?

Dennis Foley is the novel's villain, Foley is a member of the Kennedy Administration and is a cold, bony man with the air of a former athlete—self-aware and contemptuous—who stares out of pale blue eyes and changes facial colors rather than expressions when pleased or annoyed. He always wears a black tie with a PT-109 tie clasp, and affects JFK's mannerisms. JFK sends Foley to Paris to inform French President Charles de Gaulle as to who is running the world, but de Gaulle refuses to see Foley.