[20] The matter is ably discussed in Stoerk, "Völkerrecht und Völkercourtoisie" (1908).
Not to be confounded with the rules of Comity are the rules of morality which ought to apply to the intercourse of States as much as to the intercourse of individuals.
IV RELATIONS BETWEEN INTERNATIONAL AND MUNICIPAL LAW
Holtzendorff in Holtzendorff, I. pp. 49-53, 117-120—Nys, I. pp. 185-189—Taylor, § 103—Holland, Studies, pp. 176-200—Kaufmann, "Die Rechtskraft des internationalen Rechts" (1899)—Triepel, "Völkerrecht und Landesrecht" (1899)—Anzilotti, "Il diritto internazionale nei giudizi interni" (1905)—Kohler in Z.V. II. (1908), pp. 209-230.
Essential Difference between International and Municipal Law.
§ 20. The Law of Nations and the Municipal Law of the single States are essentially different from each other. They differ, first, as regards their sources. Sources of Municipal Law are custom grown up within the boundaries of the respective State and statutes enacted by the law-giving authority. Sources of International Law are custom grown up within the Family of Nations and law-making treaties concluded by the members of that family.
The Law of Nations and Municipal Law differ, secondly, regarding the relations they regulate. Municipal Law regulates relations between the individuals under the sway of the respective State and the relations between this State and the respective individuals. International Law, on the other hand, regulates relations between the member States of the Family of Nations.
The Law of Nations and Municipal Law differ, thirdly, with regard to the substance of their law: whereas Municipal Law is a law of a Sovereign over individuals subjected to his sway, the Law of Nations is a law not above, but between Sovereign States, and therefore a weaker law.[21]
Law of Nations never per se Municipal Law.