Until his election as president in 1908, Taft's political career was one of appointments to judicial and administrative positions.  In Cincinnati, he served as prosecuting attorney (1881-1882), assistant county solicitor (1885-1887), and state superior court judge (1887-1890); nationally, he held the positions of U.S. solicitor general (1890-1892) and federal circuit court judge (1892-1900).  The United States had gained administrative control of the Philippines after the Spanish-American War of 1898.  Taft was named in 1900 to head the Second Philippines Commission, and then served as the colony's first civil governor (1901-1904).

Taft had no desire for elective office, but coveted a seat on the U.S. Supreme Court.  Yet his commitment to finishing his work in the Philippines caused him to turn down two offers from President Roosevelt to join the high court.  He professed disgust at the suggestion that he seek the Ohio governorship in 1903 in order to position himself for the 1908 presidential nomination.  In 1904, Roosevelt convinced Taft to accept the post of secretary of war, which would allow him to continue overseeing the Philippines.  The next year, Taft again declined the president's offer of an associate justiceship.

Back in Washington, Taft's public pronouncements increasingly aligned with those of the president's.  Whereas, Taft had long opposed American intervention in Latin America, he endorsed the Roosevelt Corollary to the Monroe Doctrine and administered the construction of the Panama Canal as secretary of war.  During the 1906 congressional elections, he enthusiastically endorsed federal legislation backed by the president, such as the Pure Food and Drug and Meat Inspection Acts.  He obligingly went along when Roosevelt removed Taft's call for lower tariffs in a political speech the secretary was preparing. 

In response to criticism, Taft stated in late 1907 that he took the president's side on issues because their political principles and goals were in harmony.  "Is it possible that a man shows lack of originality, shows slaving imitation, because he happens to concur in the views of another who has the power to enforce those views:  Mr. Roosevelt's views were mine long before I knew Mr. Roosevelt at all.  ... I am not to be driven from adherence to those views."

The president also believed that their thinking harmonized, and for the secretary's loyalty Roosevelt endorsed Taft as the best man to continue his policies.  With the president's strong public backing, Taft had the nomination sewn up by the time the Republican Convention met, winning in a landslide on the first ballot.  Following Taft's victory in the general election, Roosevelt wrote to George Trevelyan, the British historian, "Taft will carry on the work substantially as I have carried it on.  His policies, principles, purposes and ideals are the same as mine ..."  

Roosevelt would change his mind and challenge Taft by running as an independent in 1912.  Although Taft was instinctively more conservative than his predecessor, Roosevelt had moved further and further to the left over his political career.  The new rivalry would cause both men to lose to Democrat Woodrow Wilson, but Taft later fulfilled his ambition of serving as chief justice of the U.S. Supreme Court (1921-1930).