IV.

"The existence of states," says Montesquieu, "is like that of man, and the first have the right to make war for their proper preservation; the latter have the right to kill in the case of natural defence. In the case of natural defence I have the right to kill, since my life is my own, as the life of him who attacks me belongs to himself. * * * From the right of war follows that of conquest, which is the consequence: it ought then to follow the spirit. * * * It is clear when the conquest is made, the conqueror has no longer the right to kill, since he is no longer in the position of natural defence, or for his proper preservation.

"That which has made them think thus (right to kill), is that they have believed that the conqueror had the right to destroy society, whence they have concluded that they had that to destroy the men who composed it, which is a false consequence extracted from a false principle. Because the society should perish, it does not follow that the men who form it ought also to perish. Society is a union of men, and not men: the citizen can perish and the man remain. From the right to kill in conquest, politics have derived the right to enslave; but the consequence is as badly founded as the principle."

There are certain rules that arise from the principle of self-preservation, and form what Wolff calls "the voluntary law of nations." "Hence it follows that all nations have a right to repel by force what openly violates the law of the society which nature has established among them, or that directly attacks the welfare and safety of that society. At the same time care must be taken not to extend this law to the prejudice of the liberty of nations."