On June 15, 1898, in Faneuil Hall, Boston, the civil rights attorney Moorfield Storey proclaimed, “A war begun to win the Cubans the right to govern themselves should not be made an excuse for extending our sway over other alien peoples. The fundamental principles of our government are at stake.” Opponents of expansionism had gathered with him, alarmed that the War of 1898 might become one of conquest. Underscoring their clamor, on that same day the United States reached a Joint Resolution to annex Hawai‘i as a military necessity. 

In November 1898, activists launched the Anti- Imperialist League (AIL), which campaigned across the country and reached a membership of thirty thousand people. The AIL decried territorial expansion, arguing that it was against U.S. democratic principles. Storey served as president of the AIL from 1905 until 1921 and as president of the National Association for the Advancement of Colored People (NAACP) from 1909 until 1929.