Treaty, a binding formal agreement, contract, or other written instrument that establishes obligations between two or more subjects of international law (primarily states and international organizations), whereas a convention is a multilateral instrument of a law-making, codifying, or regulatory nature. Conventions are usually negotiated under the auspices of international entities or a conference of states. These treaties had been in the play from the times of kings and lords, for instance, truces, pacts, territorial treaties, water treaties, mining treaties etc. All these ancient informal and oral, sometimes formal and written, are the basic foundation for modern day treaties. In modern days, too, these water treaties, mining treaties, commerce treaties prevail and help in the glib and serene functioning between two or more nations. Now, all these treaties are governed by the laws, principles and ordains laid by Vienna Convention on the law of treaties.
Over the time, these treaties and conventions have evolved as the source of law and Vienna Convention on the law of treaties is the major event and played a pivotal role in the making these treaties binding and accountable towards law.
TREATIES AND CONVENTIONS AS SOURCE OF LAW
These treaties are made for two or more states to bind themselves in an agreement, so that no one violates the laws of treaty of a particular subject-matter. These treaties act as the law and helps in maintain the peace and array between the two nations. These treaties can be of any kind that could help in the calm and serene functioning of different subject-matters between the two or more countries. These are often negotiated by the diplomats or representatives to whom the power is given to argue on the behalf of the state, but usually the president negotiates the treaty and signs it, too as he/she is the first citizen of the state.
The treaties have been divided into two types; bilateral and multilateral treaties that governs the rules and principles laid between the nations.
Bilateral treaties are those treaties that is signed between two nations or states to conduct the affairs with each other. These kinds of treaties are easy to negotiate as it is much easier to make an agreement with one nation as juxtaposed with the multilateral treaty. For example, Indus Water treaty signed between the two hostile nations of India and Pakistan, so that the water could be easily accessible to both the nations without any dispute arising amongst them
Multilateral treaty is the treaties that is signed between three or more nations. Such treaties usually take place between the homelands of the specific region or continent. These treaties create unique challenges due to its intricacy. Negotiation becomes very arduous between the parties and these treaties requires a significant amount of time and coordination between these nations. For example, the Maastricht treaty that created the European Union (EU), this treaty was signed by various nations of Europe for the easy conduct of trade and commerce, and it also introduced the single currency for all the nations, who signed the Treaty. 
These treaties can be classified according to their object; Political treaties, commercial treaties, constitutional and administrative treaties, treaties relating to criminal justice, treaties relating to civil justice and treaties codifying international law. But it is very difficult to categorise a particular treaty into these above-mentioned classifications.
These treaties act as the foundation for the international law. They help in maintain the peace on borders, flow of water, mining, sea routes, trading etc., the stability is maintained and diplomatic relations remain in tandem between the countries. Cooperation, tranquillity and security can be maintained even between the hostile nations with the help of these treaties. They act as an accord that empowers the international laws.
VIENNA CONVENTION ON THE LAW OF TREATIES (VCLT), 1969
It is an international agreement between diverse states and nations that was drafted by the International Law Commission of the United Nations. It is also known as “Treaty on Treaties”. It laid the comprehensive rules, procedures, guidelines, principles and ordains for how the treaties are defined, drafted, amended, construed and generally operated. It was adopted on May 23, 1969 and that came into force on January 27, 1980. The VCLT is considered a codification of customary international law and state practice concerning treaties. 
Only signed or written treaties between states are covered by the convention. The agreement’s terms and scope are defined in the Part I (Introduction) of convention. Part II (Conclusion and Entry into force of Treaties) lays out the procedures for concluding and adopting treaties, including parties’ consent to be bound by treaties and the formation of reservations—that is, declining to be bound by one or more specific sections of a treaty while accepting the remainder. Part III (Observance, Application and Interpretation of Treaties) describes how treaties are applied and interpreted, and Part IV (Amendment and Modification of Treaties) discusses how treaties can be modified or amended. The purpose of these parts is to codify existing customary law. Part V (Invalidity, Termination and Suspension of the Operation of Treaties) of the convention, which is the most essential part, lays out the grounds and rules for invalidating, terminating, or suspending treaties, as well as a provision allowing the International Court of Justice jurisdiction over disputes arising from the application of those provisions. 
SIGNIFICANT ARTICLES UNDER VCLT, 1969
The treaty involves several challenges before it becomes a source of law. The agreement codifies a number of fundamental principles of modern international law. It defines a treaty as “a written international agreement between states controlled by international law,” and declares that “every state has the competence to conclude treaties.”
Article 1 limits the convention’s application to written treaties between states, excluding treaties between states and international organisations or treaties between international organisations. The Vienna Convention on the law of treaties laid down the basic steps for the formation of treaty:
Article 7 (Full power) laid down the principles for the negotiation and discuss the rules and regulations of the particular subject-matters and it gives full power to the representatives to argue and negotiate the terms and norms for the welfare of their state and nation.
Article 9(1) states that “The adoption of the text of a treaty takes place by the consent of all the States participating in its drawing up” and Article 9(2) states that “The adoption of the text of a treaty at an international conference takes place by the vote of two thirds of the States present and voting, unless by the same majority they shall decide to apply a different rule.”
Article 10 enables the state to authenticate the treaty by averring, “The text of a treaty is established as authentic and definitive: (a) by such procedure as may be provided for in the text or agreed upon by the States participating in its drawing up; or (b) failing such procedure, by the signature, signature ad referendum or initialling by the representatives of those States of the text of the treaty or of the Final Act of a conference incorporating the text.”
There are specific provisions and norms by which the parties to the treaty can express their consent. Article 11(Means of expressing consent to be bound by a treaty) encourages the parties to express their consent in different forms of treaty acceptance. Article 12 (Consent to be bound by a treaty expressed by signature) lays down the principle of consent expressed by signature. Article 14(Consent to be bound by a treaty expressed by ratification, acceptance or approval) lays the provisions for the consent by ratification. Article 15 deals with provisions and norms of accession; in which a state who is not initially the part of the treaty or was not participant at the time of negotiation and subsequently wanted to become the part of the treaty.
Under the Article 24, the parties or nations to the treaty becomes legal bound to the terms and norms of the treaty, after they have negotiated the terms and expressed their consent. After just one state expressed its consent doesn’t those norms have come into force, but it is obligatory that the other negotiating states to express their respective consent for treaty to came in effect. 
SPECIAL PROVISIONS UNDER VCLT, 1969
Article 19 (Formulation of reservations) empowers the provisions of making reservations as it enables a negotiating state to agree upon the certain part of the treaty and not on the other part, which is not in the welfare of its own. Parties can also make declaration to the treaty in addition to reservations. These are not legally binding as the reservation itself but it is just a written statement formally attached to the treaty that clarifies the meaning of the terms and reservations of the treaty.
The negotiating party to the treaty has the authority to make the treaty, a self-executing treaty, which comes into effect in each and every region of the territory as soon as the consent is expressed to the terms and norms of the treaty, whereas the party can also give the power to state government for passing the legislation in the state assembly and then, making the norms of the treaty to be bound, this type of treaty is also known as non-self-executing treaty.
Articles 26 defines pacta sunt servanda and states, “Every treaty in force is binding upon the parties to it and must be performed by them in good faith”.
Articles 40 (Amendment of multilateral treaties) and 41 (Agreements to modify multilateral treaties between certain of the parties only) allow members to freely alter treaties as long as each member is given notice and the opportunity to participate. Members may agree to amend treaties as they see fit, unless the original treaty expressly prohibits specific changes. Treaty withdrawal, also known as treaty termination, occurs when a treaty’s legal effect is no longer recognised by a treaty member.
Article 53 proclaims peremptory rule and A state can withdraw from a treaty under Article 54 (Termination of or withdrawal from a treaty under its provisions or by consent of the parties), if the treaty expressly authorises it or if all other parties agree. and Article 62 proclaims fundamental change of circumstance. 
These treaties and conventions are the building blocks for the international law and helps it acting as the source of law. Vienna Convention on the law of treaties was the great initiative that was took with great perception and foresightedness by the leaders of the world at the time of 1969. This convention aided plethora of nations to be in amicable relations with the nations, who were previously hostile with one another and has a great history of their animosity and rivalry. All the parts, sections and articles are defined such that they act as the protector of international law and even, if the dispute arises the parties could appeal and file a suit in International Court of Justice (ICJ). The nations who are previously at mammoth disparity and antipathy are now working hand-in-hand. This convention empowered the state to come close to one another and work towards making our globe, a better place to live, and same happened when they came together as one to save their mother earth to sign the Paris agreement. The VCLT established the guidelines and the nations need abide it as line-by-line and need to work under its homage, for qualifying their signed document as Treaty, a source of law.
Author’s Name: Gurrashmeet Singh (Dr. B.R. Ambedkar National Law University, Sonipat)
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