Unlike other immigrants to the United States, Japanese and other Asians were not permitted to become naturalized American citizens until 1952. Under existing laws, naturalization was limited to "free white persons and to aliens of African nativity and to persons of African descent." Despite many attempts by Japanese immigrants (Issei) to gain citizenship, they were usually rejected on the grounds that the Issei were neither white nor black. The 1922 Supreme Court case Ozawa v. U.S. cemented the status of the issei as "aliens ineligible to citizenship" once and for all. It wasn't until 1952 with the passage of the Immigration and Nationality Act that Issei were finally allowed to become naturalized U.S. citizens.