Philander Chase Knox (May 6, 1853 – October 12, 1921) was an American lawyer, bank director and politician.
A member of the Republican Party, Knox served in the Cabinet of three different presidents and represented Pennsylvania in the United States Senate.
Born in Brownsville, Pennsylvania, Knox became a prominent attorney in Pittsburgh, forming the law firm of Knox and Reed.
With the industrialists Henry Clay Frick and Andrew Mellon, Knox also served as a director of the Pittsburgh National Bank of Commerce.
In early 1901, he accepted appointment as United States Attorney General.
Knox served under President William McKinley until McKinley was assassinated in September 1901, and Knox continued to serve under President Theodore Roosevelt until 1904, when he resigned to accept appointment to the Senate.
Knox won re-election to the Senate in 1905 and unsuccessfully sought the 1908 Republican presidential nomination.
In 1909, President William Howard Taft appointed Knox to the position of United States Secretary of State.
From that post, Knox reorganized the State Department and pursued dollar diplomacy, which focused on encouraging and protecting U.S.
Knox returned to private practice in 1913 after Taft lost re-election.
He won election to the Senate in 1916 and played a role in the Senate's rejection of the Treaty of Versailles.
Knox was widely seen as a potential compromise candidate at the 1920 Republican National Convention, but the party's presidential nomination instead went to Warren G.
While still serving in the Senate, Knox died in October 1921.