William Howard Taft was a central participant at the birth of American imperialism. He won praises for his work with the Philippine Islands, first as head of the commission created to restore the Islands to a peaceful state, then as the first civil governor. He gave up this office to become Secretary of War under President Theodore Roosevelt in 1905. In his position in the Cabinet Taft had direct or indirect oversight over most of America's scattered empire.
By March, 1909, when Taft succeeded Roosevelt in the Presidency, the constitution of the American empire had largely been formulated, even if strictly speaking, it had not been formalized. Civil governments had been set up in Puerto Rico, Hawaii, and the Philippine Islands. The “insular cases” of 1901 had defined the limits of claims of the dependent peoples upon the Constitution of the United States; the new possessions were neither foreign nor domestic, and thus even though the Constitution did not follow the flag, tariffs might. The only armed resistance to American control—in the Philippines—had long since ended. It was then to the surprise and dismay of President Taft that tiny Puerto Rico immediately presented a hostile challenge to his new administration, the constitutional rebellion known as the appropriation crisis of 1909.