The point of discussion of this paper is to analyze the need and importance of common approval and assent of states in law of states. It considers the particular situations in which consent of states is crucial for binding the states to specific international law. The paper at hand also figure out the circumstances in which, without the common consent of states, a law is binding and, to follow it, is an obligation on states. This paper precisely evaluates the significance and binding nature of international treaties and customary law.
The first query to answer is that to what extent International Law is based on common consent of states.
According to Oppenheim that International Law is the compilation of different rules on which various countries give their mutual consent after the observation and the recognition of those rules. Those states which ratified, the international treaty or agreement, are bound to follow that.
Consent is the key element of international law. It plays a crucial part in its development. The objective of consent is to assure the sovereignty of states. and protect one’s welfare and interest.
There are two schools of thoughts on “necessity of common consent of states.”
i. Positive school ii. Naturalist school
The proponents of positive school gave stress on the consent of states. According to them, will of states is necessary to make the international law binding. On the other hand, naturalists backed their opinion by saying that international law can prevail in the absence of the consent of the states.
I, personally, support the positive school on international law, which states that will is a necessary ingredient to make binding international law. It is a general rule that a rule or treaty is not binding on states unless states gave their consent to it. The consent of a state is necessary to prevail and maintain the doctrine of state sovereignty.
Lotus case (1927) is the landmark case of international law. In this case, Permanent Court of International Justice established that the rules, which are mandatory to follow and binding upon nations, have emerged from their own free will. The court also stated that countries are having the right to figure out those principles which will carry out the correlations of various nations. Any international law that is made without will of a state contravene the supremacy of the state.

The second query to answer is that to what extent, consent play a role in making a treaty and customary law, binding in nature.
The primary source of international law is Treaties. These are of growing importance in international law. It is listed in Article 38(1)(a) of the Statute of the International Court of Justice, as international conventions. Treaty is the most strong source of international law. It contains the mutual promises of the states parties consenting to it, which of course is very powerful evidence that the terms agreed to should be ‘binding’ on them. Indeed, the idea of mutual consent underlies one of the most basic principles of international law_ the principle of pacta sunt servanda, means that states are bound to keep promises they make.
The Vienna Convention on the Law of Treaties defines a treaty in article 2(1)(a) as an international agreement concluded between states in written form and governed by international law. Consent is a necessary element to constitute treaty. Moreover, the preface of document of Vienna Convention on the Law of Treaties introduces the doctrine of will among various states.
Where there is no consent, a country is not duty-bound to follow the treaty. Consent is also not considered when a nation coerced or mislead to make a treaty, and it is out of their own will. According to article 52 and article 53 of the Vienna Convention on the Law of Treaties, A treaty is null and void when one country signs a treaty under force or threat or in fear of harm. The consent in a situation of duress has no legal consequences.
While determining the implication of rules in different states, consent is important. According to Watson, an impartial approach of connection between different countries is consent as it is a scale to measure the legitimacy of binding of rules. In international law, absence of a free will of state create doubt and uncertainty, as weather rules and laws are obligatory on state or not.
As explained above, common consent of the state is required to establish the obligation upon states. An international rule, if lack, consent of country, will either be ignored or will declare null and void.
Under international law, if we take an example of “principle of jus cogens”, consent is not an compulsory element to bind the state to some particular law. Jus cogens norms are peremptory norms from which no derogation is permitted. Under article 53 of the Vienna Convention on the Law of Treaties, a peremptory norm is a “norm undertaken and identified by many states of the world in a mass in which nobody is allowed to bring change, it can be changed only by a new tradition of international law of the same nature”.
Examples include the prohibition of slavery, genocide, torture etc
Customary international law listed as a source of international law under article 38(1)(b) of the Statute of the International Court of Justice. These norms must be general practice accepted as law. In historical case, Colombia v. Peru, also known as Asylum case (1950), ICJ held that the rule invoked should be in accordance with a constant and uniform usage practiced by the states in question.
As explained above, the customary international law should be exercised in the state by accepting the practice as sufficient to create legal obligations on a state (opinio juris). So ultimately, a state will not be restricted to abide by an obligation emerging from the customary international law.
International law is important to make this world a better place. Sometimes, arm-twisting is essential to secure human rights, because in these days, many states are reluctant to act in accordance with the international human rights rules. Such disregard for the law eventually promotes transgression. So in this case, states should be confined to follow these international rules with or without their approval. Guzman submits that it is better not to introduce a law if there is no restriction to follow it.
The Domingues Case (supra) gives prominence to the point, that in compliance with the international law, consent is important to set up an obligation/law upon states is objectionable. However, obligations like outlawing oppression and humiliation of humans should be strictly implemented in the states without giving any regard to their consent.
To put it briefly, under international law, there are, however some cases where a state’s consent is required for exercise and implementation of a law. But at the same time, international law also says that some rules can be applied to the state even without its permission. And consent, despite its importance, shouldn’t be called for every time because of certain drawbacks which are witnessed through this paper.