[290] Principles of Moral and Political Philosophy, Book VI. ch. 12. The Law of Nations is, then, the Supreme Law of the Commonwealth of Nations, governing their relations with each other, determining their reciprocal rights, and sanctioning all remedies for the violation of these rights. To the Commonwealth of Nations this law is what the Constitution and Municipal Law of Massachusetts are to the associate towns and counties composing the State, or what, by apter illustration, the National Constitution of our Union is to the thirty several States which now recognize it as the supreme law. * * * * * But the Law of Nations,--and here is a point of infinite importance to the clear understanding of the subject,--while anticipating and providing for controversies between nations, recognizes and establishes War as final Arbiter. It distinctly says to nations, "If you cannot agree together, then stake your cause upon _Trial by Battle_." The mode of trial thus recognized and established has its own procedure, with rules and regulations, under the name of Laws of War, constituting a branch of International Law. "The Laws of War," says Dr. Paley, "are part of the Law of Nations, and founded, as to their authority, upon the same principle with the rest of that code, namely, upon the fact of their being _established_, no matter when or by whom."[291] Nobody doubts that the Laws of War are established by nations. [291] Principles of Moral and Political Philosophy, Book VI. ch. 12. It is not uncommon to speak of the _practice_ of War, or the _custom_ of War,--a term adopted by that devoted friend of Peace, the late Noah Worcester. Its apologists and expounders have called it "a judicial trial,"--"one of the highest trials of right,"--"a process of justice,"--"an appeal for justice,"--"a mode of obtaining rights,"--"a prosecution of rights by force,"--"a mode of condign punishment." I prefer to characterize it as an INSTITUTION, established by the Commonwealth of Nations as Arbiter of Justice. As Slavery is an Institution, growing out of local custom, sanctioned, defined, and established by Municipal Law, so War is an Institution, growing out of general custom, sanctioned, defined, and established by the Law of Nations.