According to the preamble to contract law, treaties are a source of international law. If an act or absence is condemned by international law, the law will not accept its international legality, even if it is authorized by domestic law.  This means that in the event of a conflict with domestic law, international law will always prevail.  Article 46-53 of the Vienna Convention on Treaty Law establishes the only ways to declare treaties invalidable under international and non-applicable 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. Modern contracts, whatever the purpose, generally contain articles in which definitive authentic copies of the contract are filed and how any subsequent disputes over their interpretation are settled peacefully. The distinctions are mainly related to their method of authorisation. Contracts must be advised and approved by two-thirds of the senators present, but executive agreements alone can be executed by the President. Some contracts give the president the power to fill gaps through executive agreements rather than additional contracts or protocols. Finally, agreements between Congress and the executive branch require the approval of the House of Representatives and the Senate before or after the president signs the treaty. Contracts are not necessarily binding on signatories.
Since obligations under international law have traditionally arisen only from the agreement of states, many treaties explicitly allow a state to withdraw as long as it follows certain notification procedures. For example, the Single Convention provides that the treaty expires when the number of parties is less than 40 due to termination. Many contracts explicitly prohibit withdrawal. Article 56 of the Vienna Convention on Treaty Law provides that when a treaty is silent on whether it can be denounced or not, there is a rebuttable presumption that it cannot be denounced unilaterally, unless Australian treaties generally fall into the following categories: extradition, postal agreements and monetary instructions, trade and international conventions. Currently, the likelihood of international agreements being implemented by an executive agreement is ten times higher. Despite the relative simplification of executive agreements, the President still often chooses to continue the formal process of concluding an executive agreement in order to gain congressional support on issues that require Congress to pass appropriate enforcement laws or means, as well as agreements that impose complex long-term legal obligations on the United States. For example, the agreement of the United States, Iran and other countries is not a treaty. A treaty is a formal and binding written agreement that is concluded by actors in international law, usually sovereign states and international organizations, but may involve individuals and other actors.  A treaty can also be described as an international agreement, protocol, treaty, convention, pact or exchange of letters. Regardless of terminology, only instruments that are binding on the parties are considered treaties of international law.  A treaty is binding under international law.
In the case of contractual agreements between Congress and the executive branch and executive agreements, the nature of the termination may be dictated by the underlying contract or by the underlying status on which the agreement is based.189 In the case of contract executive agreements, the Senate may indicate that the President cannot enter into executive agreements under the authority of the Treaty without the authorization of the Senate or Congress. , Congress may dictate how the denunciation in the law for the approval or implementation of the agreement