Deportation, according to the U.S. Immigration and Naturalization Service, is “the formal removal of an alien from the United States when the alien has been found removable for violating immigration laws.” Throughout the history of the United States individuals have been deported for such reasons as committing subversive acts against the government, fraudulently obtaining legal residency, and having a criminal record. In the last two decades of the twentieth century, for example, a number of immigrants to the United States were deported when it was determined that they had been prison guards in Nazi concentration camps during the 1930s and 1940s. Sometimes these individuals had been living quietly in the United States for nearly half a century.
Until nearly the end of the twentieth century, deportation was considered separate from exclusion, the act of denying an alien entry into the United States With the passage of the Illegal Immigration Reform and Immigrant Responsibility Act in 1996, deportation and exclusion procedures were consolidated, effective April 1, 1997.