Following World War II and the establishment of the United Nations, international law began to parallel the elements of the UN Charter. First signed in 1945 in San Francisco, the UN Charter provided a framework for post-war international relations and dispute resolution.
EQUALITY OF STATES
One of the major elements influencing the post-war international law principles was the independence of the West’s former colonial territories. With influence from the USSR, these newly independent states demanded complete sovereignty and an equal voice at the table in the UN General Assembly. While the UN Security Council maintained the five permanent members (US, USSR, France, Britain, and China) and their veto power as an exclusive group, there was no similar arrangement in the General Assembly. One of the key elements influencing the scope, terms, and approach of treaties and international relations during the Cold War was the vast number of emerging nations that we could outvote and have, as a block, significant influence in the United Nations.
This equality and sovereignty extended to the affairs of the State, the rights of jurisdiction over its citizens and those within its territory, and the preservation of the integrity of the borders. The smallest nation has the same sovereign rights as a superpower under most elements of international law.
NON-INTERVENTION
A second principle from the UN Charter was that the default approach for international relations was not to intervene in another nation’s internal or external affairs. This principle includes using coercion or force against elements of foreign governments, executives, legislatures, or the judiciary, in addition to the direct use of force. Conversely, this also extends to assisting or harboring factions or groups that seek to influence elements of foreign governments or involvement in actual civil wars. There is an exception for “national liberation” movements – those fighting to restore the independence of a formerly independent state or a racially oppressed group (instead of an ethnic group – which does not share in these protections under international law).
Issues arising under this principle include whether propaganda, economic sanctions, “quarantines,” and other non-military acts qualify as “intervention” under international law. Each would be evaluated on a case-by-case basis, and little has been done to enforce or define these as “intervention” in international tribunals.
PROHIBITION OF THE USE OF FORCE
The use of force, except in self-defense, is prohibited under international law. This includes peremptory strikes against a nation in anticipation of an attack and the use of insurgents or other agents to act on behalf of one State against another. In addition to the direct use of force, the mere threat of using force or the application of economic actions such that the peace is threatened also falls under this prohibition.
Interestingly, supplying aid to insurgents is not considered a force sufficient to trigger self-defense defense to a law violation. Neither is the use of force against insurgents conducting “national liberation” movements, as defined above. This definition and principle are a direct result of the disproportionate number of emerging nations in the UN General Assembly during the Cold War and the influence of the USSR in supporting these “liberation” movements.
PEACEFUL RESOLUTION OF DISPUTES
International law dictates that the parties must endeavor to resolve their dispute in a non-threatening manner in any dispute, and the use of force is prohibited. The failure of a state to enter or engage in good faith negotiations to resolve any conflict is a de facto violation of this principle of international law.
HUMAN RIGHTS AND SELF-DETERMINATION OF PEOPLE
The end of the colonial period brought to light the lack of self-determination of the subjugated colonies. One of the fundamental principles of the post-war period was the right of people to determine their government and path forward and the right of all people to fundamental human rights, such as the right not to be subjected to torture or capricious arrest. The people held these rights against the State instead of between states, like most international laws. Provided for by the UN Conference on Human Rights in 1966 and expanded since then, this is a fundamental tenet of the UN and results in UN intervention globally in conflicts.
Along with the human rights element is the right to self-determination. This is predominantly viewed in terms of race instead of ethnicity and applies to historically significant divisions. While international law favors the integrity of borders and does not generally support secession as falling under this principle, when applied to colonial subjugation, military occupation, or racial minorities, the principle allows for self-determination outside the existing national structure.
On these principles, the UN was chartered, and the evolution of international law developed in the post-war era. Most elements we see today can be traced back to one of these principles, if not economics.