By the time of WWII, the United States had a large population of ethnic Germans. Among residents of the United States in 1940, more than 1.2 million persons had been born in Germany, 5 million had two native-German parents, and 6 million had one native-German parent. Many more had distant German ancestry. During WWII, the United States detained at least 11,000 ethnic Germans, overwhelmingly German nationals. The government examined the cases of German nationals individually, and detained relatively few in internment camps run by the Department of Justice, as related to its responsibilities under the Alien Enemies Act. To a much lesser extent, some ethnic German US citizens were classified as suspect after due process and also detained. Similarly, a small proportion of Italian nationals and Italian Americans were interned in relation to their total population in the US. The United States had allowed immigrants from both Germany and Italy to become naturalized citizens, which many had done by then.
