Who is Jeffrey Porter from Spencerville and what is their importance?

Jeffrey Porter has been friends with Keith and Annie since they met in college. He was against the Vietnam War in the sixties, and this belief caused a break in his friendship with Keith, especially when Keith was drafted to go to Vietnam. During Keith's first tour, Jeffrey even wrote him a letter in which he calls him a baby killer. Jeffrey later apologizes to Keith, and they renew their friendship. Jeffrey even helps Keith in his desire to reunite with Annie.