From 1896 to 1899, Garfield served in the
Ohio State Senate. He was an influential advisor to President
Theodore Roosevelt, serving as a Member of the
United States Civil Service Commission from April 24, 1902 to February 25, 1903 alongside
John Robert Procter and
William Dudley Foulke, preceded by
William A. Rodenberg and succeeded by Alford Cooley. From 1903 to 1907, he served as Commissioner of Corporations at the
Department of Commerce and Labor, where he conducted investigations of the meat-packing, petroleum, steel, and railroad industries. From 1907 to 1909, he served in Roosevelt's
Cabinet as
Secretary of the Interior, where he advocated for the conservation of natural resources but, notably, approved the request from
San Francisco to dam the
Hetch Hetchy valley in
Yosemite National Park. He left this post on March 4, 1909, and returned to his law practice in
Cleveland. In 1909, he received an
honorary LL.D. degree from the
University of Pittsburgh. Garfield was a contender for the Ohio Republican gubernatorial nomination in the
1910 election but withdrew from the convention when it endorsed the
Taft Administration; the convention went on to nominate future president
Warren G. Harding in the third round of balloting. During the
1912 presidential election, he was a key supporter of Roosevelt's bid for a third term. In the
1914 election, he made an unsuccessful bid for
Governor of Ohio on the
Progressive Party ticket. ==World War I==