There are several reasons why an otherwise valid and agreed treaty can be rejected as a binding international convention, most of which pose problems related to contract formation. [Citation required] For example, the Japan-Korea treaties of 1905, 1907 and 1910, which ended in series, were protested; [17] and they were declared “null and void” in the 1965 Treaty on Fundamental Relations between Japan and the Republic of Korea. [18] While the Vienna Convention provides for a general dispute resolution mechanism, many contracts establish a process outside the Convention to resolve disputes and alleged infringements. This can be done by a specially convened body, in reference to a court or body set up for this purpose, such as the International Court of Justice, the European Court of Justice or procedures such as the World Trade Organization`s understanding of dispute resolution. Depending on the contract, such a procedure may result in fines or other enforcement action. In addition to treaties, there are other less formal international agreements. These include efforts such as the Proliferation Security Initiative (PSI) and the G7 Global Partnership Against the Proliferation of Weapons of Mass Destruction. Although the PSI has a “declaration of prohibition principles” and the G7 Global Partnership includes several statements by G7 heads of state and government, it also does not have a legally binding document that sets specific obligations and is signed or ratified by member states. Articles 46-53 of the Vienna Convention on Treaty Law define the only ways to declare treaties invalid – which is considered unenforceable and void in international law. A treaty is invalidated either because of the circumstances in which a State party has acceded to the treaty, or because of the very content of the treaty. Cancellation is separate from termination, suspension or termination (addressed above), all of which involve a change in the consent of the parties to a previously valid contract, not the nullity of that consent in the first place. Second, some states do not have a state of succession, but cease to exist; in such cases, state ratifications are not taken into account.

In some cases, these states are subdivided into an existing state, as at the time when East Germany was part of the Federal Republic of Germany and was part of Tanzania as Zanzibar (Republic of Tanganjika and Zanzibar first). In other cases, the state that no longer exists is divided into two or more states, with none of the states being classified as a formal successor state. The SFR-Yugoslavia (now six independent states) and Czechoslovakia (now two independent states) are examples of the latter. In this situation, the new states generally declare the treaties ratified by the state that no longer exists that they continue to have strengths for the new state. Such a declaration is considered by the new state to be a “ratification.” [c] International treaty law has been largely codified by the Vienna Convention on Treaty Law, which sets out the rules and procedures governing the establishment, modification and interpretation of contracts, as well as the resolution and resolution of disputes and alleged infringements. [6] Treaties are considered to be one of the oldest manifestations of international relations as the main source of international law. [7] If a treaty is ratified by almost every recognized state in the world, the principles of law contained in the treaty can become an international customary law.