[§ 60. Jurisdiction over Aliens]
Citizens of one state, when sojourning in a foreign state, have a dual relationship by which they may claim certain privileges, both from their native state and from the foreign state.
(a) The native state naturally has jurisdiction of a qualified sort over its subjects even when they are in a foreign state.
(1) The right to make emigration laws may lead to restrictions binding in a foreign state. A state may banish its subjects. No other state is obliged to receive them, however.
(2) A state may recall its citizens for special reasons, as in the case of Greece in 1897, when Greek citizens were recalled for military service.
(3) There is much difference of opinion upon the question of penal jurisdiction of the native state over its subjects who have committed crimes in a foreign state. In general American and English authorities agree that penal law is territorial. Some of the continental authorities take the view that a citizen on his return may be punished for crimes committed in a foreign state. The English law takes this position in certain crimes, as treason, bigamy, and premeditated murder. Usually a crime committed upon a vessel in a foreign harbor is held as within the jurisdiction of the state of the vessel's registry.
(4) A state may interfere to protect its subjects in a foreign state, thus extending its authority in their behalf. This has been frequently done to protect Western sojourners in Eastern states, e.g. the demands of Germany, in 1898, for concessions from China on account of injuries to missionaries. These demands, accompanied by a naval demonstration, resulted in the cession of Kaio-Chau.
(b) The jurisdiction of a state over aliens within its territory is very extensive.
(1) The absolute right of exclusion of all foreigners would hardly be maintained by any civilized state, though it could be deduced from the doctrine of sovereignty. Whether justly or not, Japan and China have been compelled by force to cede certain rights to states demanding admission for their citizens.
(2) The right of expulsion is, however, generally maintained. This right should, however, be exercised most carefully, as the fact of admission carries with it some obligation on the part of the admitting state.