The flow of immigration (encouraged by the Burlingame Treaty of 1868) was stopped by the Chinese Exclusion Act of 1882. This act outlawed all Chinese immigration to the United States and denied citizenship to those already settled in the country. Renewed in 1892 and extended indefinitely in 1902, the Chinese population declined until the act was repealed in 1943 by the Magnuson Act. (Chinese immigration later increased more with the passage of the Immigration and Nationality Act of 1952, which abolished direct racial barriers, and later by the Immigration and Nationality Act of 1965, which abolished the National Origins Formula.