American diplomat, candidate for the United States Senate, and one-time husband of Doris Duke, "the richest girl in the world". Cromwell married Doris Duke in 1935 and was divorced from her in 1943.

Cromwell's first wife was Automotive heiress Delphine Dodge, the only daughter of Horace Dodge of Grosse Pointe, Michigan, one of the two co-founders of the Dodge Motor Company, predecessor of the Chrysler Company. Cromwell and Delphine were the parents of one daughter, Christine, born in 1923. They were divorced in 1928.

In 1940, for 142 days, he was the United States Envoy Extraordinary and Minister Plenipotentiary to Canada. He resigned to run for Senator of New Jersey in the 1940 elections, where he was defeated.

Cromwell’s sister Louise Cromwell Brooks (c. 1885 – c. Aug 1973) was the first wife of Douglas MacArthur and the third wife of Lionel Atwill.

http://en.wikipedia.org/wiki/James_H._R._Cromwell

James Henry Roberts Cromwell (1896-1990) — also known as James H. R. Cromwell — of Somerville, Somerset County, N.J.; Weehawken, Hudson County, N.J. Born in New York, New York County, N.Y., June 4, 1896. Son of Oliver Eaton Cromwell and Lucretia (Roberts) Cromwell; married, June 20, 1920, to Delphine Dodge (divorced, 1928) (sister of Horace Elgin Dodge, Jr.); married, February 13, 1935, to Doris Duke (divorced, 1943) (daughter of James Buchanan Duke); married 1948 to Maxine McFetridge; brother of Louise Cromwell (aunt by marriage of Douglas MacArthur II). Democrat. Served in the U.S. Navy during World War I; vice-president, Peerless Motor Car Company; U.S. Minister to Canada, 1940; delegate to Democratic National Convention from New Jersey, 1940; candidate for U.S. Senator from New Jersey, 1940; president, Chemwood Corporation, pulp and paper manufacturers. Member, American Legion; Veterans of Foreign Wars; Military Order of the World Wars; Marine Corps League; American Academy of Political and Social Science. Died in 1990.

http://politicalgraveyard.com/occ/automfg.html