Diplomacy: Come to the Party

Adlai Stevenson once said of Marietta Tree, "When you find someone closely identified with the intellectual and aristocratic communities who is also a positive, active, working Democrat, it tends to encourage everyone in the party." Mrs. Tree, 47, is a willowy (5 ft.

10 in., 135 Ibs.) blonde patrician, the granddaughter of Dr. Endicott Peabody, founder of Massachusetts' Groton School. Once divorced, she is now the wife of British Investment Magnate Arthur Ronald Lambert Field Tree, a grandson of the original Marshall Field.

Marietta would be an addition to most any party, certainly not excluding those that she throws herself. She...