Alien foe

An alien enemy is an individual who, due to permanent or temporary allegiance to a hostile power, is regarded as an enemy in wartime. Under federal law, an alien enemy is a native, citizen, or subject of a foreign nation, state, or sovereign with which the United States is at war.

The term alien enemy, as it is defined by federal law, does apply easily to individuals who belong to organizations that are not affiliated with a foreign sovereign. Nevertheless, the treatment of such Aliens mirrors treatment permitted by federal law for aliens who are citizens of foreign nations.