Ambassador Hillary Clinton?
These days going from secretary to ambassador would be considered a demotion, and any secretary would be more likely to resign than accept the post. However, before transatlantic flights became common, a few former secretaries were given assignments to spend their later years serving as ambassadors in London and Paris. Edward Stettinius, Jr. was the last former secretary to serve as an ambassador. In 1945, President Truman made him America's first ambassador to the United Nations.
