A large number of the modern writers are in favor of the extradition of subjects in the same manner as aliens, and it is evident that the drift of international practice, as shown by the treaties of the last quarter-century, is toward the refusal to grant protection to a subject who has sought refuge in his native state after committing a crime abroad.
In case the accused whose extradition is demanded is a citizen of a third state, the practice is not uniform, though the best authorities seem to favor the granting of the extradition only after communication with and assent of the third state, on the ground that the state to which the subject has fled is responsible to the third state for its treatment of him. This practice has been followed in many European treaties.
Ordinarily, not all criminals are liable to extradition, though treaty stipulations may cover cases usually excepted. Those accused of political crimes have, since the early part of the nineteenth century, been more and more generally exempt from extradition. During the last quarter of the nineteenth century few treaties have been made which do not make political criminals specifically non-extraditable. Political crimes accompanied by attacks upon the person of the sovereign or of those holding political office or position are not, however, in the above category, but are usually extraditable.
(b) Even when an accused person is extradited there are limitations as to the jurisdiction of the state to which he goes. The trial must be for the offense or offenses enumerated in the treaty. For example, a treaty between two states enumerates among extraditable crimes murder, and does not enumerate larceny. A fugitive from one of the countries is accused of both murder and larceny. The country surrendering the criminal would not permit the trial of the criminal for any other crime than murder, until the criminal should have had opportunity to return to the state from which he was surrendered. For many years Great Britain claimed that a person surrendered in accordance with an extradition treaty should be tried only for the specific offense for which he was surrendered. The United States desired to include other offenses provided the person had been once surrendered. This position of Great Britain was accepted by the treaty of July 12, 1889.[195]
(c) The conditions necessary for a claim for extradition are: (1) that the crime shall have been committed within the territorial or maritime jurisdiction of the state making the demand, (2) that there be sufficient evidence of guilt to establish a case, and (3) that the application be from the proper authority and in the proper form.[196]
(d) The procedure in cases of extradition is based on definite principles. As it is an act of sovereignty, it must be performed by agents of the sovereign person, who for this purpose, although generally engaged in other functions, are executive officers.[197] The general rule is that the demand for extradition shall be made through the ordinary diplomatic channels. In colonies and under special circumstances an officer of first rank may be the medium of the demand.
The person demanded may be placed under provisional arrest pending the full proceedings of extradition.[198]
Reasonable evidence of the identity of the person and of the facts of the crime must be furnished by the state making the demand.
In case a person is demanded by two states, his native state and a third state in which he has committed a crime, it is customary to grant the request of the state in which he has committed the crime.
When a person is demanded on the ground of separate crimes committed in both states as above, if the crimes are equally grave, the request of his native state is granted. Sometimes, however, when the third state offers to surrender the fugitive to his native state after he has paid the penalty of his crime, the request of the third state is granted.