American Imperialism By KBlair2018 Mar 2, 1872 Pago Pago Jan 1, 1889 McKinley Tariff Apr 14, 1898 Spanish American War Apr 19, 1898 Teller Amendment Jul 6, 1898 Annexation of Hawaii Feb 6, 1899 Annexation of Philipines Sep 6, 1899 Open Door Policy Dec 31, 1899 The Boxer Rebellion May 22, 1903 Platt Amendment Dec 31, 1903 Monroe Doctrine