The Naturalization Act of 1906 was the first law in US history that provided for denaturalization. The same act also federalized the naturalization process for the first time in US history. (Prior to passage of the law, immigrants sought naturalization in state courts.) Federalization allowed millions of European immigrants to become US citizens with ease. Causes for denaturalization under the 1906 Act included fraud, racial ineligibility, and lack of “good moral character.” In 1907, Congress expanded the laws on loss of citizenship by marking for expatriation all US-born citizens who had naturalized in foreign nations and women who had married foreigners. These laws were revised in subsequent years, most notably through the 1940 Nationality Act and the 1952 McCarran Walter Act, which added voting in foreign elections or serving in the armed forces of another country as additional reasons for loss of citizenship. (Curious readers born in the United States should turn to the section titled “Important Information” in their passports where they can find a list of circumstances that can, on paper, result in loss of citizenship.)
According to Patrick Weil (Yale Univ.), who’s written extensively about denaturalization, between 1907 and 1973 the US government recorded 22,026 instances of naturalization cancellations. These numbers rise when Weil adds in instances of expatriation of US-born citizens: between 1945 and 1977, Weil calculates, 120,770 US citizens lost their nationality. But the numbers are likely much higher: no reliable data exists for the number of women who were automatically considered expatriated upon marrying a foreigner, or for citizens who were administratively determined to have lost their citizenship for violating the nationality laws. (A remarkable but brief story appearing in the September 16, 1946, issue of Time magazine reports that “70,000-odd U.S. citizens living in Canada . . . automatically lost their U.S. citizenship” as a result of voting in Canadian elections. “Expatriated Americans” were instructed by the US Consulate in Toronto to “regain their lost citizenship simply by applying to any U.S. diplomatic officer in Canada.” It’s unclear how many actually did.)