The American Anti-Imperialist League was an organization established on June 15, 1898, to battle the American annexation of the Philippines as an insular area. The anti-imperialists opposed forced expansion, believing that imperialism violated the fundamental principle that just republican government must derive from "consent of the governed." The League argued that such activity would necessitate the abandonment of American ideals of self-government and non-intervention—ideals expressed in the United States Declaration of Independence, George Washington's Farewell Address and Abraham Lincoln's Gettysburg Address. The Anti-Imperialist League was ultimately defeated in the battle of public opinion by a new wave of politicians who successfully advocated the virtues of American territorial expansion in the aftermath of the Spanish–American War and in the first years of the 20th century.