The _reservatio mentalis_, too, of "_rebus sic stantibus_" is an unwarrantable and wicked reservation. Nothing prevents a decent man when making a contract from adding a clause reserving the right to terminate it if the essential conditions should change. If the other party to the contract does not agree to this, well, then the contract cannot be concluded. But to sign it with the mental reservation that one will disavow one's signature if the obligations undertaken become irksome, that is swindling. There is one consideration so simple that it is inconceivable that those who break contracts do not realize it. In some concrete case the leader of the state judges it to be profitable to the state to disregard good faith. What guarantee has he that his judgment is right? He is a man, and no man is infallible. But all mankind have made good faith the foundation of their life in communities, and if a single man has the temerity to draw a conclusion violating the immutable convictions and doctrines of all mankind, he must be mad not to see that most probably he is wrong and that all mankind in every age and every clime is right. I have left out of consideration the fact that any possible advantage arising from the breach of faith would not excuse him morally, and setting aside the ethical aspect of the case, I dwell only on the logical argument. There is one case and one only in which a contract is not binding, either on the state or on the private individual, and that is when the signatory was forced to enter upon it with a knife at his throat. Obligations which a victor imposes on his defeated and disarmed opponent are by their very nature invalid. The old cry of Brennus: "_Vae victis!_" is might and cannot constitute a right. Civil law calls this kind of thing compulsion and decrees that it invalidates any contract. Only a pedantic mind, stupid and depraved, immersed in hair-splitting trickery and incapable of a straight thought, could complacently maintain in the face of all common sense that might and compulsion, far from doing away with right, are the source of all right. The silly formula coined for this is: "Might is right." Might may be a fact, but it is not right. The source of right is not might but Morality, which might disavows and destroys. The necessary condition of any obligation which is to be valid is freedom. Kant proved this, but his proof was unnecessary, for it is self-evident. A forced treaty is no treaty, for it is the victor's fist which has guided the hand of the vanquished, and it is he who wrote the latter's signature under the document. The will, the consciousness of the seeming signatory were absent at the time.