In the 1922 case of Takao Ozawa v. United States, Japanese immigrant Takao Ozawa sought to become a naturalized U.S. citizen under the Naturalization Act of 1906 which allowed only "free white persons" and "aliens of African nativity and persons of African descent" to be eligible for naturalization. Arguing that his skin was lighter than many 'white' people, he claimed eligibility for citizenship based on color rather than race or nationality. The Supreme Court unanimously ruled against him stating that being 'white' meant being Caucasian, not having light-colored skin; thus excluding non-Caucasian Asians from gaining citizenship through naturalization regardless their assimilation into American society or personal characteristics such as education level or moral standing. This ruling upheld racial restrictions in immigration law until they were finally abolished by Immigration and Nationality Act in 1952.

In the Supreme Court case of Takao Ozawa v. United States, there was no dissenting opinion recorded. The court unanimously ruled against Ozawa, a Japanese immigrant who sought naturalization under U.S laws that only granted citizenship to free white persons and those of African descent or nativity. Despite his assimilation into American society and self-identification as "white," the court held that "white" referred strictly to Caucasian race based on scientific theories at the time, thereby excluding him from eligibility for citizenship due to his racial background.