The separation between the two is often unclear and is often politicized in disagreements within a government over a treaty, because a treaty cannot be implemented without a proper change in national legislation. When a treaty requires laws of application, a state may be late in its obligations if its legislator does not pass the necessary national laws. 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. Another situation may occur when one party wishes to create an obligation of international law, but not the other party. This factor has been at work in the run-up to talks between North Korea and the United States on security guarantees and the proliferation of nuclear weapons. 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. 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. 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. If a contract does not contain provisions for other agreements or measures, only the text of the treaty is legally binding. In general, an amendment to the Treaty only commits the States that have ratified it and the agreements reached at review conferences, summits or meetings of the States Parties are not legally binding. The Charter of the United Nations is an example of a treaty that contains provisions for other binding agreements. By signing and ratifying the Charter, countries have agreed to be legally bound by resolutions adopted by UN bodies such as the General Assembly and the Security Council. Therefore, UN resolutions are legally binding on UN member states and no signature or ratification is required.