Australian contracts generally fall into the following categories: extradition, postal agreements and payment vouchers, trade and international conventions. Articles 46 to 53 of the Vienna Convention on the Law of Treaties define the only ways of invalidating treaties – considered inapplicable and void by international law. A treaty is annulled, either because of the circumstances in which a State Party has acceded to the Treaty or because of the content of the treaty itself. The declaration of invalidation is separate from revocation, suspension or termination (above) which involves a modification of the consent of the parties to a previously in force contract and not the invalidation of that consent. In international law and international relations, a protocol is usually an international treaty or agreement that complements an earlier treaty or international agreement. A protocol may amend the previous contract or add additional provisions. The parties to the previous agreement are not obliged to adopt the protocol. This is sometimes clearer by referring to it as an “optional protocol”, especially when many parties to the first agreement do not support the protocol. A treaty is a formal and binding written agreement concluded by actors of international law, usually sovereign states and international organizations, but also individuals and other actors.
 A treaty may also be designated, inter alia, as an international agreement, protocol, pact, convention, pact or exchange of letters. [Citation required] Contracts are not necessarily permanently binding on the signatory parties. Since international obligations are traditionally considered only on the basis of the consent of States, many treaties expressly allow a State to withdraw as long as it follows certain notification procedures. For example, the Single Convention on Narcotic Drugs provides for the termination of the contract when, as a result of denunciations, the number of parties falls below 40. Many contracts expressly prohibit withdrawal. Article 56 of the Vienna Convention on the Law of Treaties provides that, where a contract does not say whether it can be terminated or not, there is a rebuttable presumption that it cannot be terminated unilaterally, unless a multilateral treaty is concluded between several countries that establishes rights and obligations between each party and any other party.  Multilateral treaties can be regional or involve states from around the world.  “Mutual guarantee” contracts are international treaties, for example.
B the Treaty of Locarno, which guarantees each signatory an attack by another.  Under international law, a treaty is any legally binding agreement between states (countries). A treaty can be called a convention, protocol, pact, agreement, etc.c is the content of the agreement, not its name, that makes it a treaty. Thus, the Geneva Protocol and the Biological Weapons Convention are the two treaties, although no one has the word “treaty” in its name. Under U.S. law, a treaty is specifically a legally binding agreement between countries that requires ratification and the “advice and approval” of the Senate. . .