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. 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. The BTWC prohibits the development, stockpiling, supply, storage and manufacture of biological active substances and toxins “of species and quantities that have no justification for prophylactic, protective or other peaceful purposes,” as well as weapons, equipment and delivery vehicles “intended to use such products or toxins for hostile purposes or in armed conflict.” The IHR (2005) is an international agreement between 194 States Parties and the World Health Organization on surveillance, sunshine and response to all events that could pose a threat to international public health. The objective of the IHR (2005) is to prevent, protect, control and respond to a public health response to the spread of diseases internationally, in a manner adapted to public health risks, limited to them, avoiding unnecessary intervention in international transport and trade. (International Health Regulations, Article 2). For more information, please see THE LA fact sheets.
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. 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.