War then is a relation, not between man and man, but between State and State, and individuals are enemies only accidentally, not as men, nor even as citizens,[1] but as soldiers; not as members of their country, but as its defenders. Finally, each State can have for enemies only other States, and not men; for between things disparate in nature there can be no real relation. Furthermore, this principle is in conformity with the established rules of all times and the constant practice of all civilised peoples. Declarations of war are intimations less to powers than to their subjects. The foreigner, whether king, individual, or people, who robs, kills or detains the subjects, without declaring war on the prince, is not an enemy, but a brigand. Even in real war, a just prince, while laying hands, in the enemy's country, on all that belongs to the public, respects the lives and goods of individuals: he respects rights on which his own are founded. The object of the war being the destruction of the hostile State, the other side has a right to kill its defenders, while they are bearing arms; but as soon as they lay them down and surrender, they cease to be enemies or instruments of the enemy, and become once more merely men, whose life no one has any right to take. Sometimes it is possible to kill the State without killing a single one of its members; and war gives no right which is not necessary to the gaining of its object. These principles are not those of Grotius: they are not based on the authority of poets, but derived from the nature of reality and based on reason. The right of conquest has no foundation other than the right of the strongest. If war does not give the conqueror the right to massacre the conquered peoples, the right to enslave them cannot be based upon a right which does not exist No one has a right to kill an enemy except when he cannot make him a slave, and the right to enslave him cannot therefore be derived from the right to kill him. It is accordingly an unfair exchange to make him buy at the price of his liberty his life, over which the victor holds no right. Is it not clear that there is a vicious circle in founding the right of life and death on the right of slavery, and the right of slavery on the right of life and death?