The list below comprises the ten most important international treaties after World War II. These treaties consist of a formal and binding written agreement entered into by actors in international law, which are in most cases sovereign states and international organizations. This list consists of the most crucial and influential international treaties post World War II, along with further insight of their purpose and importance.

When creating this list, we intended to display here those ten international treaties which have significantly impacted the course of international law, and resulted in peaceful relations and positive development. The list does not reflect any political opinion of the authors.

1. United Nations Charter

The United Nations Charter has been established as a means of saving ‘’succeeding generations from the scourge of war’’. This has derived from the failure of the League of Nations to arbitrate the conflicts that led up to World War II. Thenceforth, the Allies made a proposal as early as 1941 which established a new international body to maintain peace in the post-war world. The idea of the United Nations began to be articulated in August 1941, when U.S President Franklin D. Roosevelt and British Prime Minister Winston Churchill signed the Atlantic Charter, which proposed a set of principles for international collaboration in maintaining peace and security. The term was first officially used on 1 January 1942, when representatives of 26 Allied Nations met in Washington D.C., and signed the Declaration by the United Nations, which endorsed the Atlantic Charter and presented the united war aims of the allies. Fast-forward to 25 April 1945, the United Nations Conference on International Organization convened in San Francisco with 50 nations represented. Three months later, during which time Germany had surrendered, the final Charter of the United Nations was unanimously adopted by the delegates. On 26 June, it was signed; the Charter which consisted of a preamble and 19 chapters divided into 111 articles, called for the UN to maintain international peace and security, promote social progress and better standards of life, strengthen international law and promote the expansion of human rights. The principal organs of the UN, as specified in the Charter, were: the Secretariat, the General Assembly, the Security Council, the Economic and Social Council, the International Court of Justice, and the Trusteeship Council.

2. The Vienna Convention on Diplomatic Relations

The treaty was adopted on 18 April 1961, by the United Nations Conference on Diplomatic Intercourse and Immunities held in Vienna, Austria, and first implemented on 24 April 1964. The Convention codifies the rules for the exchange and treatment of envoys between states, which have been firmly established in customary law for hundreds of years. It has become an almost universally adopted Convention with 179 states party to it. This Convention is fundamental to the conduct of foreign relations and ensures that diplomats can conduct their duties without threat of influence by the host government. As is stated in the preamble of the Convention, the rules are intended to facilitate the development of friendly relations among nations, irrespective of their differing constitutional and social systems. The purpose of such privileges and immunities is not to benefit individuals but to ensure the efficient performance of the functions of diplomatic missions. The Convention requires diplomats to obey local laws; however, the only sanction permissible under the Convention, in the absence of a waiver of immunity, is expulsion. This prevents the potential abuse by local authorities of the power of a state’s law enforcement system. Reciprocity also forms an effective sanction for the observance of the rules of the Convention.

3. Paris Peace Treaties

The Paris Peace Treaties were signed on 10 February 1947 following the end of World War II in 1945. The Paris Peace Conference lasted from 29 July until 15 October 1946. The victorious wartime Allied powers (principally the United Kingdom, Soviet Union, United States and France) negotiated the details of peace treaties with Italy, Romania, Hungary, Bulgaria and Finland. The treaties allowed the defeated Axis powers to resume their responsibilities as sovereign states in international affairs and to qualify for membership in the United Nations.

The settlement elaborated in the peace treaties included payment of war reparations, commitment to minority rights, and territorial adjustments including the end of the Italian colonial empire in Africa, Greece, and Albania, as well as changes to the Italian–Yugoslav, Hungarian–Czechoslovak, Soviet–Romanian, Hungarian–Romanian, French–Italian, and Soviet–Finnish borders. The treaties also obliged the various states to hand over accused war criminals to the Allied powers for war crimes trials. Another interesting historical fact is that Hungary’s WWII defeat was sealed in a new peace treaty, which restored the Trianon frontiers, with a rectification in favor of Czechoslovakia and the Soviet Union. It imposed on Hungary a reparations bill of $300 million and limited its armed forces. The implementation of the treaty’s provisions was to be supervised by a Soviet occupation force, a large contingent of which remained in the country until June 1991.

4. Universal Declaration of Human Rights (UDHR)

The Universal Declaration of Human Rights, which was adopted by the UN General Assembly on 10 December 1948, was the result of the experience of the Second World War. With the end of that war, and the creation of the United Nations, the international community vowed never again to allow atrocities like those of that conflict to happen again. World leaders decided to complement the UN Charter with a road map to guarantee the rights of every individual everywhere. The document they considered, and which would later become the Universal Declaration of Human Rights, was taken up at the first session of the General Assembly in 1946. The Universal Declaration of Human Rights (UDHR) therefore, is a document that acts like a global road map for freedom and equality – protecting the rights of every individual, everywhere. It was the first time countries agreed on the freedoms and rights that deserve universal protection in order for every individual to live their lives freely, equally and in dignity. Work on the UDHR began in 1946, with a drafting committee composed of representatives of a wide variety of countries, including the USA, Lebanon and China. The drafting committee was later enlarged to include representatives of Australia, Chile, France, the Soviet Union and the United Kingdom, allowing the document to benefit from contributions of states from all regions, and their diverse religious, political and cultural contexts. The first draft of the Declaration was proposed in September 1948 with over 50 Member States participating in the final drafting. By its resolution 217 A (III) of 10 December 1948, the General Assembly, adopted the Universal Declaration of Human Rights with eight nations abstaining from the vote but none dissenting. The entire text of the UDHR was composed in less than two years. At a time when the world was divided into Eastern and Western blocks, finding a common ground on what should make the essence of the document proved to be a colossal task.

5. Fourth Geneva Convention

While the first three conventions dealt with combatants, the Fourth Geneva Convention was the first to deal with humanitarian protections for civilians in a war zone. The Convention, which was adopted in 1949, takes account of the experiences of World War II. It contains a rather short part concerning the general protection of populations against certain consequences of war (Part II), leaving aside the problem of the limitation of the use of weapons. The great bulk of the Convention (Part III – Articles 27-141) puts forth the regulations governing the status and treatment of protected persons; these provisions distinguish between the situation of foreigners on the territory of one of the parties to the conflict and that of civilians in occupied territory. Therefore, a unique feature of the four Geneva Conventions and their additional Protocols lies in the collective responsibility of the parties. The parties have undertaken to implement such responsibility through a common goal in which “to respect and to ensure respect for the Convention in all circumstances.” It underscores the particular legal nature of the conventions, their universality and the essential value of the body of humanitarian law they incorporate.

6. The Convention on the Prevention and Punishment on the Crime of Genocide (Genocide Convention)

The Convention on the Prevention and Punishment of the Crime of Genocide (Genocide Convention) is an instrument of international law that codified for the first time the crime of genocide. The Genocide Convention was the first human rights treaty adopted by the General Assembly of the United Nations on 9 December 1948 and signified the international community’s commitment to ‘never again’ after the atrocities committed during the Second World War. Its adoption marked a crucial step toward the development of international human rights and international criminal law as we know it today. The definition of the crime of genocide, as set out in the Convention, has been widely adopted at both national and international levels, including in the 1998 Rome Statute of the International Criminal Court (ICC). Importantly, the Convention establishes on State Parties the obligation to take measures to prevent and to punish the crime of genocide, including by enacting relevant legislation and punishing perpetrators, “whether they are constitutionally responsible rulers, public officials or private individuals” (Article IV). That obligation, in addition to the prohibition not to commit genocide, have been considered as norms of international customary law and therefore, binding on all States, whether or not they have ratified the Genocide Convention.

7. Convention on the Reduction of Statelessness (1961 Convention)

The Convention on the Reduction of Statelessness was adopted on 30 August 1961 and entered into force on 13 December 1975. It complements the 1954 Convention relating to the Status of Stateless Persons and was the result of over a decade of international negotiations on how to avoid the incidence of statelessness. Together, these two treaties form the foundation of the international legal framework to address statelessness, a phenomenon which continues to adversely affect the lives of millions of people around the world. Although the Universal Declaration of Human Rights confirms that everyone has the right to a nationality, it does not set out the specific nationality to which a person is entitled. This absence of clear rules may result in statelessness. States therefore developed a series of additional standards, which were adopted in 1961 in the form of the Convention on the Reduction of Statelessness (“1961 Convention”), in recognition of the need for further international cooperation and agreement to prevent and reduce statelessness. Henceforth, the 1961 Convention is the leading international instrument that sets rules for the conferral and non-withdrawal of citizenship to prevent cases of statelessness from arising.

8. International Covenant on Civil and Political Rights (ICCPR)

The Covenant was adopted by the U.N. General Assembly in 1966 and came into force in 1976.

The ICCPR is a key international human rights treaty, providing a range of protections for civil and political rights. The ICCPR obligates countries that have ratified the treaty to protect and preserve basic human rights, such as: the right to life and human dignity; equality before the law; freedom of speech, assembly, and association; religious freedom and privacy; freedom from torture, ill-treatment, and arbitrary detention; gender equality; the right to a fair trial; right family life and family unity; and minority rights. The Covenant compels governments to take administrative, judicial, and legislative measures in order to protect the rights enshrined in the treaty and to provide an effective remedy.

9. International Covenant on Economic, Social and Cultural Rights (ICESC)

The International Covenant on Economic, Social and Cultural Rights is a multilateral treaty adopted by the United Nations General Assembly on 16 December 1966. Resolution 2200A (XXI) came into force from 3 January 1976. It commits its parties to work toward the granting of economic, social, and cultural rights (ESCR) to the Non-Self-Governing and Trust Territories and individuals – including labor rights and the right to health, the right to education, and the right to an adequate standard of living. As of July 2020, the Covenant has 171 parties. The ICESCR (and its Optional Protocol) is part of the International Bill of Human Rights, along with the Universal Declaration of Human Rights (UDHR) and the International Covenant on Civil and Political Rights (ICCPR), including the latter’s first and second Optional Protocols.

10. International Covenant on the Elimination of All Forms of Discrimination (ICERD)

The ICERD is a United Nations Convention that was adopted and opened for signature by the United Nations General Assembly on 21 December 1965, and entered into force on 4 January 1969. It is a third-generation human rights instrument, which commits its members to the elimination of racial discrimination and the promotion of understanding among all races. It also requires its parties to outlaw hate speech and criminalize membership in racist organizations. The Convention also includes an individual complaints mechanism, effectively making it enforceable against its parties. This has led to the development of a limited jurisprudence on the interpretation and implementation of the Convention. The Declaration makes four principal points:

I) Any doctrine of racial differentiation is socially unjust, dangerous, and has no justification in theory or practice;

II) Racial discrimination violates fundamental human rights, endanger friendly relations among peoples, co-operation among nations, and international peace and security;

III) Racial discrimination harms not only those who are its objects but also those who practise it;

IV) A world society free of racial segregation and discrimination, factors which create hatred and division, is a fundamental aim of the United Nations.