Because of differing citizenship laws in Japan and the United States, Nisei born before 1924 were citizens of both countries, a status referred to as "dual citizenship." Dual citizenship status became part of standard criticisms of Japanese Americans by nativist and anti-Japanese groups. Rising tensions between Japan and the U.S. in the 1930s highlighted the issue and led Japanese Americans to launch efforts to encourage Nisei to renounce their Japanese citizenship. Even after changes in Japanese law ended automatic dual citizenship for Nisei in 1924, anti-Japanese groups used the issue of dual citizenship to justify wartime measures aimed at stripping Nisei of their U.S. citizenship.
Origins and Extent of Dual Citizenship
Until 1924, Japanese citizenship laws granted citizenship to all children of Japanese nationals regardless of their place of birth. The legal term for this form of citizenship is called jus sanguinis , or the right of blood. Germany and Italy are notable examples of other countries that followed this same model of citizenship. The United States, on the other hand, granted citizenship to all persons born in the United States, regardless of ancestry, beginning in 1868 with the 14th Amendment to the Constitution, which states: "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside." The legal term for citizenship by birthplace is called jus soli , or the right of the soil. Granting citizenship to all persons born within a country is typical of countries that received most of the world's immigrants, and at the turn of the Twentieth Century, the United States received more immigrants than any other single country.  These two sometimes contradictory methods of granting citizenship by birth and by blood gave Nisei children born to Japanese national parents on U.S. soil dual citizenship in Japan and the United States automatically up through 1924. 
In 1924, the same year Congress shut the door on legal immigration from Japan and severely restricted immigration from southern and eastern Europe with the National Origins Act , the Japanese government revised its citizenship laws so that the Nisei born in the United States after this date would no longer gain automatic Japanese citizenship. Parents who wished to pass their citizenship on to their children had two weeks to register their desires with a Japanese consulate, and children who wished to renounce their Japanese citizenship could do so with far fewer restrictions than before. In the past, young men of military age (over the age of 17 years) could not renounce their Japanese citizenship and, if resident in Japan, were obligated to serve in the military. After the law changed in 1924, Nisei could renounce their Japanese citizenship even if they were within the ages of compulsory military service, and thus free themselves from any possible military obligation to Japan. 
In the wake of changes in Japanese citizenship law, the number of Nisei dual citizens declined steadily between 1924 and 1941. From 1924 to 1930, only one out of three children born to Japanese parents was registered with the Japanese consulate. During the same period, 40 percent of Nisei born before 1924 took advantage of the new provision for dual citizens to renounce their Japanese citizenship. In 1927, the Consul General of Japan reported from San Francisco that over 51,000 of approximately 63,000 Nisei, slightly more than 80 percent held dual citizenship.  Other reports using data from a census conducted under the auspices of the Japanese government indicated that by 1930 only 47 percent of Nisei in California held dual citizenship.  After 1930, fewer and fewer parents declared Japanese citizenship for their children, and Nisei born before 1924 continued to renounce their Japanese citizenship. On the eve of World War II approximately 70 percent of Nisei retained U.S. citizenship alone.  While these statistics are only estimates that are subject to the biases of those keeping and reporting them, it is safe to assume that the majority of Nisei were not dual citizens at the beginning of World War II, and the vast majority of those who might have been dual citizens in theory were completely unaware of their dual status.
Perils of Dual Citizenship
Lawmakers, many of whom assumed that Asian immigrants could not be assimilated into America racially, culturally or socially, questioned the legal status and loyalty of Nisei dual citizens in 1920 as a part of Congress' investigation into what some called the problems related to immigration. Some political leaders argued with a fair amount of hysteria that Japan's policy of granting automatic citizenship to the children of emigrants offered proof that it was planning a social if not military invasion of the United States as part of Japan's attempts to expand its empire.  When the House committee investigating immigration interviewed one future Nisei leader, James Sakamoto , about his dual citizenship, he described it as a mere legal technicality that did not have any bearing on his loyalty to the United States.
When Congress passed its most restrictive immigration legislation in the nation's history in 1924, effectively ending legal immigration from Japan, questions about Nisei dual citizenship seemed to fade for a time. Yet the subject of dual citizenship remained a tool useful to those who were interested in challenging Nisei rights in the United States. The United States government did not officially recognize Japanese citizenship law, nor did it officially recognize dual citizenship as an acceptable legal status for any of its citizens. Officially, the United States only recognized singular citizenship despite the reality that many American-born citizens were dual nationals, including children born to German and Italian immigrants. Nisei dual citizenship became a matter of importance primarily to those who sought to limit Japanese Americans' rights in the United States, or more important for those whose ultimate goal was to deny citizenship to anyone of Japanese ancestry and thereby weaken the 14th Amendment.
After the Selective Service Act was passed in 1940 in preparation for America's likely entry into World War II, the War Department took steps to resolve the issue of Nisei dual citizenship. The War Department sponsored legislation over the summer and into the fall of 1941 that would force Nisei to choose between their U.S. and Japanese citizenship and go through a process of renouncing their ties to Japan and declaring loyalty to the United States. Singling out Nisei would not have been constitutional, so the proposed legislation was written in a way that applied to all dual citizens. All persons with dual citizenship, not just Nisei, entering into military service or employed in government, no matter their place of birth, race, or nationality, would have to take a formal oath of allegiance to the U.S. and renounce allegiance to all other foreign governments, or give up their U.S. citizenship, be subject to deportation, or at the very least, confinement in a "concentration camp." This bill, presented under two different house resolution numbers, H.R. 5879 and H.R. 6109, received a great deal of support but was the subject of intense debate and scrutiny. Ultimately both bills failed to pass, but testimony revealed that War Department representatives and House Representatives both favored some wartime powers that would allow the government to force Nisei to choose definitively between U.S. and Japanese citizenship.
Dual Citizenship and "Loyalty" during World War II
In an effort to address the concerns of the War Department and to fend off accusations of disloyalty, particularly after Japan bombed Pearl Harbor and the United States had declared war against Japan, Japanese American Citizens League (JACL) delegates voted at its first wartime convention held on January 11, 1942 to require that all members sign a loyalty oath. The oath read:
I, ______________, do solemnly swear that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I hereby renounce any other allegiances which I may have knowingly or unknowingly held in the past; and that I take this obligation freely without any reservation or evasion. So help me God.
This oath provided a means for Nisei to declare their allegiance to the United States and to forswear allegiance they may or may not have held to the emperor of Japan by way of dual citizenship. The JACL leadership remained keenly aware of the fears that pervaded congressional debates in the 1920s over Nisei dual citizenship and the War Department's failed attempts to sponsor legislation that would have required such an oath of dual citizens in 1941. With no such law in place, the JACL tried to resolve the issue by creating its own oath of allegiance that included a renunciation of any foreign allegiances. The JACL oath was never recognized by Congress or the War Department and in effect had no bearing on the status of Nisei during the war.
Japan's attack on Pearl Harbor provided the wartime conditions that the War Department believed would allow it to bring an end to Nisei inductions into the military until it could design a way to have Nisei resolve questions about their loyalty and citizenship. The War Department instructed Selective Service to end inductions for Nisei and to transfer Nisei into the category of enemy aliens. In 1943, before accepting volunteers for a segregated Nisei combat team, the War Department required that all adult Nisei men fill out a questionnaire that would help them assess their ties to Japan and that would provide a bureaucratic mechanism by which Nisei could resolve questions about their citizenship. This form has become known informally as the " Loyalty Questionnaire ," and conflicts over its use by both the War Department and the War Relocation Authority initiated what historians often refer to as the "loyalty registration crisis." The "Loyalty Questionnaire" was sent to all Nisei processed by Selective Service, regardless of whether or not they were incarcerated or living freely outside of the exclusion zone, and was also given to Nisei already serving in the military. The War Department's use of the form was designed to resolve its questions about the loyalty and citizenship of both current and future inductees.
Dual citizenship remained a crucial and yet poorly understood issue throughout the war and became one of the focal points of debates over whether Nisei in particular deserved any protections of due process in this time of wartime racial hysteria. In fact, each attempt to remove additional rights from Japanese Americans brought the issue of dual citizenship to the forefront, such as when the Native Sons of the Golden West sued in the Regan v. King case to remove all Nisei from voter registration lists in King County, California under the assumption that all registered Nisei were actually Japanese citizens and thus were ineligible for U.S. voting rights. The Supreme Court ruled against the petitioners and upheld Nisei rights to U.S. citizenship under the 14th Amendment. The Holman Bill, introduced by Senator Rufus C. Holman, Republican Senator from Oregon in 1942, was designed to end Nisei dual citizenship entirely by prohibiting children of immigrants from automatic citizenship by way of the 14th Amendment, but it did not pass into law. Dual citizenship seemed to provide racially motivated demagogues with justifications to ignore the Constitution or to revise the Fourteenth Amendment to strip certain groups of their U.S.-born citizenship.
Conflicts over 14th Amendment provisions for automatic citizenship continue in debates over who should and who should not be included in U.S. citizenship. Current debates focus on the children of undocumented immigrants and U.S.-born children whose parents had no intention of remaining in the U.S., particularly parents from Middle Eastern countries (see Hamdi v. Rumsfeld , 542 U.S. 507 ), who may retain competing loyalties beyond their U.S. citizenship. Japanese American wartime cases, particularly Korematsu v. United States , along with other Asian American cases such as United States v. Wong Kim Ark , have prevented special interest groups from stripping certain individuals of their U.S.-born citizenship.
For More Information
Lyon, Cherstin. Prisons and Patriots: Japanese American Wartime Citizenship, Civil Disobedience, and Historical Memory . Philadelphia: Temple University Press, 2011.
Rosenbloom, Rachel E. "Policing the Borders of Birthright Citizenship: Some Thoughts on the New (and Old) Restrictionism." Washburn Law Journal , 51, No. 2 (Spring 2012): 311-330.
- There were some notable exceptions to this rule, such as the citizenship status of Native Americans who were not granted automatic U.S. citizenship rights until 1924.
- Nationality Act of 1899, Issue 66, Official Gazette (Japan, March 16, 1899); 1916 Amendment to the Nationality Act of 1899, Issue 27, Articles 18-26, Official Gazette (Japan, March 16, 1916); Durward V. Sandifer, "A Comparative Study of Laws Relating to Nationality at Birth and to Loss of Nationality," American Journal of International Law 29 (1935): 248-279; Law No. 66, March 16, 1899 , Japanese Civil Code, Vol. III, as quoted in United States, War Relocation Authority, Wartime Exile: The Exclusion of the Japanese Americans from the West Coast (Washington, D.C.: USGPO, 1946), 33.
- Philip M. Glick, Memorandum to Dillon S. Myer, "Domicil: A Factor in regard to dual citizenship," Manzanar, California, 9 April 1943, Record Group 210, Section 16, box 229, folder 31.009-1, National Archives and Records Administration, Washington, D.C. [Hereafter cited as NARA RG 210/16]; Carey McWilliams, "Dual Citizenship," Far Eastern Survey 11, no. 23 (November 1942): 231-233; Nationality Act of 1899, Issue 66, Official Gazette (Japan, March 16, 1899); 1916 Amendment to the Nationality Act of 1899, Issue 27, Articles 18-26, Official Gazette (Japan, March 16, 1916); Sandifer, "A Comparative Study"; Law No. 66, March 16, 1899 , Japanese Civil Code.
- Elliot Grinnell Mears, Resident Orientals on the American Pacific Coast: The Asian Experience in North America: Chinese and Japanese (Chicago: University of Chicago Press, 1928), 107-08, 429, quoted in Hirabayashi v. U.S. , 320 U.S. 81 (1943), 98, fn 8.
- Edward K. Strong, The Second-Generation Japanese Problem (Stanford: Stanford University Press, 1934), 142.
- Strong, The Second-Generation Japanese Problem , 142-43; Philip M. Glick, Memorandum to Dillon S. Myer, "Domicil"; and McWilliams, "Dual Citizenship," 231-233.
- Klancy Clark De Nevers, The Colonel and the Pacifist: Karl Bendetsen, Perry Saito and the Incarceration of Japanese Americans during World War II (Salt Lake City: University of Utah Press, 2004); House, Hearing at Seattle, Washington before the House Sub-Committee on Immigration and Naturalization, 27 July 1920 , as reprinted in T. Iyenaga and Kenoske Sato, Japan and the California Problem (New York: G.P. Putnam's Sons, 1921), appendix L, 203-229.