Deportation

Deportation is the expulsion of a person or group of people from a place or country. Today the expulsion of foreign nationals is usually called deportation, whereas the expulsion of nationals is called banishment, exile, or penal transportation. Deportation is an ancient practice: Khosrau I, Sassanid King of Persia, deported 292,000 citizens, slaves, and conquered people to the new city of Ctesiphon in 542 C.E.

Military occupation

Article 49 of the Fourth Geneva Convention prohibits the deportation of people into or out of occupied territory under belligerent military occupation:

External deportation

All countries reserve the right to deport foreigners, even those who are longtime residents. In general, foreigners who have committed serious crimes, entered the country illegally, overstayed and/or broken the conditions of their visa, or otherwise lost their legal status to remain in the country may be administratively removed or deported.

In many cases, deportation is done by the government's executive apparatus, and as such is often subject to a simpler legal process (or none), with reduced or no right to trial, legal representation or appeal due to the subject's lack of citizenship. For example, in the 1930s, during the Great Depression, more stringent enforcement of immigration laws were ordered by the executive branch of the U.S. government, which led to the expulsion of up to 2 million Mexican nationals from the United States. In 1954, the executive branch of the U.S. government implemented Operation Wetback, a program created in response to public hysteria about immigration and immigrants from Mexico. Operation Wetback led to the deportation of nearly 1.3 million Mexicans from the United States.