The Philosophy of Law: Public Right, § 58: Right after War
The Right that follows after War, begins at the moment of the Treaty of Peace and refers to the consequences of the war. The conqueror lays down the conditions under which he will agree with the conquered power to form the conclusion of Peace. Treaties are drawn up; not indeed according to any Right that it pertains to him to protect, on account of an alleged lesion by his opponent, but as taking this question upon himself, he bases the right to decide it upon his own power. Hence the conqueror may not demand restitution of the cost of the war; because he would then have to declare the war of his opponent to be unjust. And even although he should adopt such an argument, he is not entitled to apply it; because he would have to declare the war to be punitive, and he would thus in turn inflict an injury. To this right belongs also the Exchange of Prisoners, which is to be carried out without ransom and without regard to equality of numbers.
Neither the conquered State nor its Subjects, lose their political liberty by conquest of the country, so as that the former should be degraded to a colony, or the latter to slaves; for otherwise it would have been a penal war, which is contradictory in itself. A colony or a province is constituted by a people which has its own constitution, legislation, and territory, where persons belonging to another State are merely strangers, but which is nevertheless subject to the supreme executive power of another State. This other State is called the ‘mother-country.’ It is ruled as a daughter, but has at the same time its own form of government, as in a separate Parliament under the presidency of a Viceroy (civitas Uybrida). Such was Athens in relation to different islands; and such is at present [1796] the relation of Great Britain to Ireland.
Still less can Slavery be deduced as a rightful institution, from the conquest of a people in war; for this would assume that the war was of a punitive nature. And least of all can a basis be found in war for a Jicreditary Slavery, which is absurd in itself, since guilt cannot be inherited from the criminality of another.
Further, that an Amnesty is involved in the conclusion of a Treaty of Peace, is already implied in the very idea of a Peace.