Deportation is the expulsion of a person or group of people from a place or country. The term expulsion is often used as a synonym for deportation, though expulsion is more often used in the context of international law, while deportation is more used in national (municipal) law. Forced displacement or forced migration of an individual or a group may be caused by deportation, for example ethnic cleansing, and other reasons. A person who has been deported or is under sentence of deportation is called a deportee. Definitions of deportation apply equally to nationals and foreigners. Nonetheless, in the common usage the expulsion of foreign nationals is usually called deportation, whereas the expulsion of nationals is called extradition, banishment, exile, or penal transportation. For example, in the United States: "Strictly speaking, transportation, extradition, and deportation, although each has the effect of removing a person from the country, are different things, and have different purposes. Transportation is by way of punishment of one convicted of an offense against the laws of the country. Extradition is the surrender to another country of one accused of an offense against its laws, there to be tried, and, if found guilty, punished. Deportation is the removal of an alien out of the country, simply because his presence is deemed inconsistent with the public welfare and without any punishment being imposed or contemplated either under the laws of the country out of which he is sent or of those of the country to which he is taken." Expulsion is an act by a public authority to remove a person or persons against his or her will from the territory of that state. A successful expulsion of a person by a country is called a deportation. According to the European Court of Human Rights, collective expulsion is any measure compelling non-nationals, as a group, to leave a country, except where such a measure is taken on the basis of a reasonable and objective examination of the particular case of each individual non-national of the group.