Newton Diehl Baker (December 3, 1871 - December 25, 1937) was an American politician in the Democratic Party, and a notable figure in the Progressive movement. He served as mayor of Cleveland, Ohio from 1911 to 1915 and as Secretary of War from 1916 to 1921.

Baker was a native of Martinsburg, West Virginia, and an 1892 graduate of Johns Hopkins University. After receiving his law degree from Washington and Lee University in 1894, Baker became the secretary to the Postmaster General, William L. Wilson.

After leaving Washington, DC, Baker moved to Cleveland, where he became active in local politics. After serving as city solicitor from 1901 to 1909, he became mayor of the city in 1911. As a city official, Baker's main interests were public power, transit reform, and city beautification.

As the United States considered whether to enter World War I, President Woodrow Wilson named Baker Secretary of War, because Baker was an acceptable candidate for politicians on both sides of the question. As Secretary of War, Baker presided over the American military involvement in the war (1917-18), including the unprecedented creation of a nationwide military draft.

After stepping down as Secretary of War in 1921, Baker practiced law, and never again served in a public office (although he was considered as a candidate for the Democratic nomination for President in 1924, 1928, and 1932). He died Christmas Day in Shaker Heights, Ohio, a suburb of Cleveland.

References

• Garraty, John A. and Mark C. Carnes. American National Biography, vol. 2, "Baker, Newton Diehl". New York : Oxford University Press, 1999.

|- style="text-align: center;" | width="30%" |Preceded by:
Lindley M. Garrison | width="40%" style="text-align: center;" |United States Secretary of War
1916–1921 | width="30%" |Succeeded by:
John W. Weeks