Treaties were an important part of European colonization and, in many parts of the world, Europeans tried to legitimize their sovereignty by signing treaties with indigenous peoples. In most cases, these contracts were in extremely unfavourable terms for Aboriginal people, who often did not understand the effects of what they signed. [Citation required] Australia`s Constitution allows the executive government to enter into contracts, but it is customary for contracts to be presented in both houses of Parliament at least 15 days before signing. Treaties are considered a source of Australian law, but sometimes require the adoption of a parliamentary act based on their nature. Contracts are managed and maintained by the Department of Foreign Affairs and Trade, which stated that the “general position under Australian law is that contracts to which Australia has joined, with the exception of those that end a state of war, are not directly and automatically included in Australian law. Signing and ratification do not allow treaties to operate on national territory. In the absence of legislation, contracts cannot impose obligations on individuals or create rights in national law. Yet international law, including contract law, is a legitimate and important influence on the development of the common law and can be used in the interpretation of laws.  Treaties can be implemented by executive measures and existing laws are often sufficient to ensure compliance with a treaty. Before 1871, the U.S. government regularly entered into contracts with Indians, but the Indians Appropriation Act of March 3, 1871 (Chapter 120, 16 Stat. 563) had a horseman (25 US. C No. 71), which effectively ended the drafting of presidential treaties by declaring that no Indian nation or Indian tribe can be recognized as a nation, tribe or independent power with which the United States can enter into contractual contracts.
After 1871, the federal government continued to maintain similar contractual relations with Indian tribes through agreements, statutes and executive ordinances.  Under international law, a treaty is a legally binding agreement between states (countries). A treaty can be called a convention, protocol, pact, agreement, etc. It 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 neither treaty in its name. Under U.S. law, a treaty is a legally binding agreement between countries that requires ratification and “consultation and approval” of the Senate. All other agreements (internationally treated) are called executive agreements, but are nevertheless legally binding on the United States under international law. 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 modify the previous contract or add additional provisions. The parties to the previous agreement are not required to adopt the protocol. This sometimes becomes more evident by calling it an “optional protocol,” especially if many parties to the first agreement do not support the protocol. UN Security Council Resolution 1540 requires all UN member states to impose effective measures against chemical, nuclear or biological weapons, their means of delivery or their related materials by non-state actors.