William Howard Taft (September 15, 1857 - March 8, 1930) was an American politician, the 27th President of the United States, the 10th Chief Justice of the United States, a leader of the progressive conservative wing of the Republican Party in the early twentieth century, a chaired professor at Yale Law School, a pioneer in international arbitration, and a staunch advocate of world peace that verged on pacifism (though the pacifists of his time did not call him one of their own).
Taft served as Solicitor General of the United States, a federal judge, Governor-General of the Philippines, and Secretary of War before being nominated for President in the 1908 Republican National Convention with the backing of his predecessor and close friend Theodore Roosevelt.
His presidency was characterized by trust-busting, strengthening the Interstate Commerce Commission, expanding the civil service, establishing a better postal system, and promoting world peace. Taft defeated Roosevelt for the Republican nomination in a bruising battle in 1912. In 1921, he became Chief Justice and is the only President to have served on the Supreme Court of the United States.