Clarkson worked in New Mexico for the
U.S. Department of the Interior and later for the
United States Naval Consulting Board. Afterwards, he was recruited for the
Council of National Defense, where he succeeded
Walter S. Gifford as Director. He served as director from December 1918 to March 1920. After the war, he published a detailed account of his time as Director of
Industrial America in World War. He was the author of two books: • An Analysis of the High Cost of Living Problem, as Director; Council of National Defense, (1919) • Industrial America in the World War; the strategy behind the line, 1917-1918, (1923) ==Personal life and death==