Before one can examine the law, one must understand what the law is. How is international law created? What constitutes international law as it is understood? The discussion here is limited to the tupes of international law and questions to be found in treaties, conventions and assurances that made up the charge of planning and waging aggressive war.
It should be noted that Germany did acknowledge the idea of an international system of law. This is evidenced by its signing of several treaties of arbitration that referenced the types of international law that were to be used in making arbitral decisions. It accepted its restrictions and obligations allowing the nation and its government to be held liable under its auspices.
Treaties and Conventions (the terms are practically synonymous for the purposes used here) are the basis of international law. From them, all understanding of the entire system flows. They carry the highest authority as they are express declarations of the law. “Treaties are contractual obligations between two or more states … outlining states’ mutual obligations, defining customary usage and achieving concerted action.[ Elements p. 223-224]” Germany understood this is how treaties worked “On the 18th of October 1933, Hitler said ‘Whatever we have signed we will fulfill to the best of our ability’”[ IMT p. 1539] as declaimed by Sir. Maxwell Fyfe at Nuremberg. There’s a bit of a caveat there that Germany could claim it is unable to fulfil the conditions of a treaty. More inability later in the chapter.
Treaties bind the parties. Unless unilateral denunciation is specifically allowed, all are bound for the duration of the treaty[ Element p. 229] - which may be perpetual. However, only the parties are bound. If a nation does not sign a treaty, then it cannot be bound by the terms. Or held to account for any alleged violation of the treaty. Nor can it seek enforcement against another nation for a violation, even if the other nation signed the treaty. Only is a nation bound with respect to the other signatories. This binding must be express. Usually shown by signature and ratification.[ The most obvious example in this time period was the United States refusal to ratify the Treaty of Versailles even though President Wilson had been one of the principal negotiators. That meant a separate peace between Germany and the US had to be concluded. It meant the US could not be forced to obey any decision of the League of Nations, but neither could it seek redress from the League.] If a treaty is revised, the new treaty comes into effect only for those signing the new treaty.[ Tobin p. 238] Consent to be bound does not automatically transfer over as consent to the revised terms must be express. If a party only signs one version, that treaty is still in effect for that country and in relation to the signatories of the that version.
Since the parties to international law are sovereign nations, a definition of sovereignty is necessary to understand why express consent is so important. A sovereign nation has the right to regulate its own affairs as it sees fit. It is free from all interference by other nations in purely internal matters. It also possesses the same and equal rights of all other nations. Only it can impose limits on itself, others cannot.[ Elements p. 35-36] This is why express consent is a necessary element to all treaties.
But what of newly created sovereign states. New created states fall into two groups. The first group involves new states that are in reality larger versions of an already established state. For this group, the international obligations of the already established state merely continue for the newly enlarged state. The USSR is an example of this group. Russia absorbed Georgia, Ukraine and other areas into the USSR. All obligations of the former Russia became the obligations of the USSR.
The second group consists of new stated carved out of old states, usually through the disintegration of empires. New States have no international commitments except those they choose to assume. Poland is the best example of this. The newly independent state of Poland after World War I was comprised of parts of Germany (which was a big problem later as will be seen), the Austro-Hungarian empire and Russia. It carried none of the obligations agreed to by any of its three forebearers but had to decide which obligations it chose to assume. It could pick and choose just like any other nation.
Sources:Transcript International Military Tribunal at NurembergElements of International Law by Henry WheatonTermination of Multipartite Treaties by Harold Tobin