For more information on international conventions, see this article on the Harvard Law Review, the Berkeley Law Research Guide and the UCLA Law Review in this article. 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 practice, the custodian of a treaty generally recognizes only ratifications of the treaty by a state recognized as a state by international law. A state can be formally recognized as such by becoming a member of the United Nations; Currently, 193 UN member states. The only non-UN countries that undoubtedly meet state standards are the Cook and Niue Islands, whose “total contractual capacity” has been recognized by the UN secretariat.  Vatican City is also widely recognized as being able to legally ratify treaties and has been recognized by the UN General Assembly as an observer state without a member state.  [b] After the adoption by the United Nations General Assembly of a resolution granting the State of Palestine observer status, UNG began to recognize its right to ratification of the treaties.
ratifications by other limited recognition states – such as the Republic of China (Taiwan); Le Kosovo; northern Cyprus; Somaliland; Sahrawi Arab Democratic Republic (Western Sahara); South Ossetia; Abkhazia; transnistria; and Nagorno-Karabakh – have generally not been recognized by treaty custodians as states that can ratify treaties, although there are some exceptions to this general rule. When a treaty is ratified by almost every recognized state in the world, the principles of law contained in the treaty can become customary international law. Customary international law applies to all states, whether or not the state has ratified a treaty that enshrines the principle. There is no set number of ratifications needed to transform the principles of a treaty into customary peoples` law, and states and experts often disagree on the principles that have and have not achieved this status. Once a treaty is in force, it is presumed, in accordance with the Vienna Convention, that it binds the parties in good faith (UN 1969). The fundamental principle of the law is the pacta sunt servanda, “agreements that are not contrary to the law and are not entered into fraudulently should be respected in all respects.” This principle applies to the interpretation of contractual terms in its practice. Article 31 of the Vienna Convention contains general rules of interpretation. However, the establishment of rules for the interpretation of contracts is considered a precautionary measure. 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.