Grant advocated restricted immigration to the United States through limiting immigration from East Asia and Southern Europe; he also advocated efforts to purify the American population though selective breeding. He served as the vice president of the Immigration Restriction League from 1922 to his death in 1937. Acting as an expert on world racial data, Grant also provided statistics for the Immigration Act of 1924 to set the quotas on immigrants from certain European countries. Even after the statute was passed, Grant continued to be irked that even a smattering of non-Nordics were allowed to immigrate to the country each year. He also assisted in the passing and prosecution of several anti-miscegenation laws, notably the Racial Integrity Act of 1924 in the state of Virginia, where he sought to codify his particular version of the "one-drop rule" into law.