Progressivism, imperialism, and World War I (1890–1918)

After the Gilded Age came the Progressive Era, whose followers called for reform over perceived industrial corruption. Viewpoints taken by progressives included greater federal regulation of anti-trust laws and the industries of meat-packing, drugs, and railroads. Four new constitutional amendments—the Sixteenth through Nineteenth—resulted from progressive activism.[73] The era lasted from 1900 to 1918, the year marking the end of World War I.[74]
U.S. Federal government policy, since the James Monroe Administration, had been to move the indigenous population beyond the reach of the federal frontier into a series of Indian reservations. Tribes were generally forced onto small reservations as farmers and ranchers took over their lands.