A question closely connected with the so-called lawfulness of employing spies, and indeed forming in one view a part of that question, is that of the lawfulness of soliciting the enemy's subjects to act as spies, or to betray him. Vattel discusses this matter in reference to considera tions both of law and of honour, or con science. " It is asked in general," he be gins, " whether it be lawful to seduce the enemy's men, for the purpose of engaging them to transgress their duty by an in f'amous treachery." It has been already stated that he lays down the principle that we may lawfully endeavour to weaken the enemy by any means not affecting the common safety of human society ; and he determines that seducing an enemy's subject does not come under this excep tion. Such measures, accordingly, he ob serves, are practised in all wars. Hut still he argues, they are not honourable, nor compatible with the laws of a pure conscience ; an evidence of which we have in the fact that generals are never heard to boast of having practised them. " If such practices," concludes Vattel, " are at all excusable, it can be only in a very just war, and when the immediate object is to save our country when threatened with ruin by a lawless conqueror. On such an occasion (as it should seem) the guilt of the subject or general who should betray his sovereign when engaged in an evi dently unjust cause would not be of so very odious a nature." But who ever heard of a war that was not thought by those engaged in it to be a just war on their own side and an unjust war on the part .of their adversaries ? So that this distinction settles nothing. It is held however to be perfectly allowable in every point of view merely to accept the offers of a traitor. In this case Vattel argues, " We do not seduce him; and we may take the advantage of his crime, while at the same time we detest it. Fugitives and deserters commit a crime against their sovereign ; yet we receive and har bour them by the law of war, as the civil law expresses it." If such offers have ever been rejected, as that of the physician of Pyrrhus, who offered to poison his mas ter, was by the Romans, he holds the act to be one of magnanimity indeed, but yet as one which no general or sovereign is bound to imitate. Or, as Grotius has ex pressed it, such a course may evince lofti ness of mind in those who pursue it, or their confidence of being able to compass their objects by open force, but has no thing to do with the question of what is lawful or unlawful,. Martens holds with
still less qualification, that we cannot con demn as an illegitimate means of carrying on a war the corruption employed to se duce the officers or other subjects of the enemy, and to tempt them either to re veal a secret or to surrender a post, or even to get up a revolt ; it is the business of each state, he argues, to protect itself from such attempts by a careful choice of the persons it employs or trusts, and by the severity of the penalties with which it punishes their treachery. " But," he adds, " it is without doubt to overleap by a great way the bounds of the law of war, and to declare itself an enemy of the whole human race, for a nation to try to stir up every other people to revolt by a general promise of assistance, as was done by the French National Convention in their decree of the 19th of November, 1792." Yet wildly absurd as this decree was, its violation of the law of nations seems to have consisted merely in its not being confined to the case of such foreign countries only as the French republic might be then at war with ; unless in deed it was intended to be taken, as it could not fail to be, for a declaration of war against all existing governments.
The proper question as to the so-called law of nations with regard to spies, is what practices are sanctioned by the general usage of independent civilized nations. Such practices as are now permitted by such usage constitute a part of this so called international law. Those practices which are not generally permitted or ac knowledged are not yet a part of such law. Persons who have occasion to write or think on this subject will find that much of the indistinctness and confusion ob servable in the treatises on the law of na tions will be removed if they will first form for themselves a clear conception of the proper meaning of the word Law, and of the improper meanings which it has also acquired ; and they will thus be en abled to give the necessary precision to terms which are used so vaguely by writers on international law. [Law ;