Usbek to the same
Magistrates must dispense justice between citizens ; each people must itself dispense justice to another people. In this second distribution of justice, one cannot apply other maxims than in the first.
From one people to another there is rarely a need for a third party to judge, because the subjects of dispute are almost always clear and easy to resolve. The interests of two nations are ordinarily so separate that one needs only love justice in order to find it ; one can hardly anticipate oneself in one’s own cause.
Such is not the case with disputes that arise between individuals. As they live in society, their interests are so linked and interconnected, there are so many of different kinds of them, that it is necessary for a third party to sort out what the greed of the parties seeks to obfuscate.
There are only two kinds of just wars : those that are waged to repel an enemy who attacks, and the rest to aide an ally that is attacked. 
There would be no justice in waging war for the prince’s personal quarrels unless the case were so grave as to merit the death of the prince or of the people that committed it. Thus a prince cannot wage war because someone has refused him an honor which is due him, or because his ambassadors have been in some way ill-used, and other similar things, no more than an individual can kill someone who refuses to yield to him.  The reason is that since the declaration of war must be an act of justice, in which the punishment must always be proportionate to the fault, the question must be whether he on whom was is declared deserves to die. For to wage war on someone is to attempt to give him a death penalty.
In public law the harshest act of justice is war, because its goal is the destruction of the society.
Retribution is the next level. It is a law which tribunals have not been able to avoid observing to measure the penalty by the crime.
A third act of justice is to deprive a prince of the advantages he can obtain from us, again proportioning the penalty to the offense.
The fourth act of justice, which must be the most frequent, is to repudiate the alliance of a people about whom one has reason for complaint. This penalty is the equivalent of the banishment established in the tribunals, which cut the guilty off from society. Thus a prince whose alliance we repudiate is thereby cut off from our society and is no longer one of its members.
There is no greater affront one can made to a prince than to repudiate his alliance, nor a greater honor than to contract it. There is nothing among men that is more glorious and even more useful for them than to have others always seeing to their preservation.
But for an alliance to bind us it must be just ; thus an alliance made between two nations to oppress a third is not legitimate, and can be violated without crime.
It is not even to a prince’s honor and dignity to ally himself with a tyrant. It is said that a monarch of Egypt had the king of Samos warned about his cruelty and tyranny, and commanded him to desist ; as he did not, he sent him word that he repudiated his friendship and his alliance. 
The right of conquest is not a right. A society can be founded only on the will of the associates ; if it is destroyed by conquest, the people becomes again free ; there is no more new society, and if the conqueror tries to form one, that is tyranny.
As for peace treaties, they are never legitimate when they require a cession or indemnification greater than the damage inflicted ; otherwise it is a pure violence, which one can always go back on, unless in order to reclaim what one has lost one is obliged to make use of means so violent that the resultant harm is greater than the good that he should derive from it.
There you have, dear Rhedi, what I call public law ; there you have the law of humanity, or rather of reason.
Paris this 4th day of the moon of Zilhagé 1716