Note 50 — Chapter XVI · The Interpretation of Treaties.

Owing to circumstances there may be a variation in the conduct, and yet no change in the principles of a state. This must frequently happen in the commercial regulations between different countries, who are obliged to vary their means to secure the unity of their end. Or if in a treaty between two nations, it is declared there shall be PERPETUAL amity, and a subsequent declaration of war by one of the parties pronounces such amicable relations to be at an end, here there is no variation in PRINCIPLE but in CIRCUMSTANCES, which render such a dissolution of the amity, that was originally intended to be perpetual, necessary to the welfare and preservation of that power, the sole object of all treaties.