Althusius on Just War

Johannes Althusius, Politica XVI:

Defence is threefold. It is the safeguarding of the associated individual members when one of them — a province, city, village, or town — suffers violence and injury, or requires the commonwealth's support for its basic interests and needs. It is, furthermore, the guaranty of free passage and public security against those who disturb, plunder, or restrict commercial activity in the territory of the associated body. It is, finally, the conduct of war.... Just cause for waging war occurs when all other remedies have first been exhausted and peace or justice cannot otherwise be obtained. There are seven just causes for declaring and waging war. The first cause is the recovery of things taken away through violence by another people. The second cause is the defence against violence inflicted by another, and the repulsion of it. The third cause is the necessity for preserving liberty, privileges, rights, peace, and tranquility, and for defending true religion. The fourth cause occurs when a foreign people deny peaceful transit through its province without good reason. The fifth cause occurs when subjects rise up against their prince and lord, do not fulfill their pledged word, and are not willing to obey him, although they have been admonished many times. The sixth reason is contumacy, which occurs when any prince, lord, or city has so contemptuously and repeatedly scorned the decisions of courts that justice cannot otherwise be administered and defended. The seventh just cause of war occurs when agreements are not implemented by the other party, when he does not keep his promises, and when tyranny is practised upon subjects....[35]

35. [This discussion of the just causes of war is supported by numerous references to the Old Testament, especially to passages in Judges, I and II Samuel, and II Kings. Beyond these, three writings are referred to more than once: Diego Covarruvias, Regulae peccatum, II, sect. 9; Peter Martyr, Commentarii (I Samuel 30; Judges 11); Henry Bocer, De jure belli, I, 17.]