20th century

On August 29, 1911, Ishi, generally considered to have been the last Native American to live most of his life without contact with European-American culture, was discovered near Oroville, California.^{[101][102][103]}
In 1919, the United States under President Warren G. Harding granted citizenship to all Native Americans who had served in World War I. Nearly 10,000 men had enlisted and served, a high number in relation to their population.^[104] Despite this, in many areas Native Americans faced local resistance when they tried to vote and were discriminated against with barriers to voter registration.
On June 2, 1924, U.S. President Calvin Coolidge signed the Indian Citizenship Act, which made all Native Americans born in the United States and its territories American citizens. Prior to passage of the act, nearly two-thirds of Native Americans were already U.S. citizens, through marriage, military service or accepting land allotments.^[105][106] The Act extended citizenship to "all non-citizen Indians born within the territorial limits of the United States."^[104]
Charles Curtis, a Congressman and longtime US Senator from Kansas, was of Kaw, Osage, Potawatomi, and European ancestry. After serving as a United States Representative and being repeatedly re-elected as United States Senator from Kansas, Curtis served as Senate Minority Whip for 10 years and as Senate Majority Leader for five years. He was very influential in the Senate. In 1928 he ran as the vice-presidential candidate with Herbert Hoover for president, and served from 1929 to 1933. He was the first person with significant Native American ancestry and the first person with acknowledged non-European ancestry to be elected to either of the highest offices in the land.
American Indians today in the United States have all the rights guaranteed in the U.S. Constitution, can vote in elections, and run for political office. Controversies remain over how much the federal government has jurisdiction over tribal affairs, sovereignty, and cultural practices.^[107]
Mid-century, the Indian termination policy and the Indian Relocation Act of 1956 marked a new direction for assimilating Native Americans into urban life.
The census counted 332,000 Indians in 1930 and 334,000 in 1940, including those on and off reservations in the 48 states. Total spending on Indians averaged $38 million a year in the late 1920s, dropping to a low of $23 million in 1933, and returning to $38 million in 1940.^[108]

World War II