The distinctions concern in the first place their type of authorization. Contracts require the deliberation and approval of two-thirds of the senators present, but only executive agreements can be executed by the president alone. Some contracts give the President the power to fill in the gaps through executive agreements and not through additional contracts or protocols. Finally, agreements between Congress and the executive branch require a majority of the House of Representatives and the Senate before or after the president signed the treaty. an agreement between two or more countries or persons that gives them power or influence See the article on the Bricker Amendment for the history of the relationship between contractual powers and constitutional provisions. A treaty is a formal and binding written agreement concluded by actors of international law, usually sovereign states and international organizations, but also individuals and other actors.  A treaty may also be designated, inter alia, as an international agreement, protocol, pact, convention, pact or exchange of letters. Regardless of the terminology, only instruments binding on the parties are considered treaties under international law.  A treaty is legally binding.
Formally, the opportunity for a country to formally join a group of countries or accept an agreement In a few rare cases, such as with Ethiopia and China of the Qing Dynasty, local governments have been able to use treaties to at least mitigate the effects of European colonization. This included learning the intricacies of European diplomatic practices, and then using treaties to prevent power from exceeding its agreement or by putting different powers in competition. [Citation required] There are several reasons why an otherwise valid and agreed treaty can be rejected as a binding international agreement, most of which raise problems related to the constitution of the treaty. [Citation required] For example, the Japanese-Korean series treaties of 1905, 1907 and 1910 were protested;  and the 1965 Treaty on Fundamental Relations between Japan and the Republic of Korea confirmed them as “already null and void.”  The end of the preamble and the beginning of the agreement itself are often indicated by the words “agreed as follows”. In other cases, such as New Zealand with the Māori and Canada with its First Nations, treaties allowed Indigenous peoples to retain a minimum of autonomy. Such treaties between colonizers and indigenous peoples are an important part of the political discourse in the late twentieth and early twenty-first centuries, the treaties discussed have an international reputation, as a study of the United Nations treaty found.   In international law and international relations, a protocol is generally an international treaty or agreement that complements an earlier treaty or international agreement. A protocol may amend the previous contract or add additional provisions. The parties to the previous agreement are not obliged to adopt the protocol. This is sometimes clearer by referring to it as an “optional protocol”, especially when many parties to the first agreement do not support the protocol.
Bilateral agreements are concluded between two States or entities.  It is possible for a bilateral treaty to have more than two parties; Thus, each of the bilateral treaties between Switzerland and the European Union (EU) has seventeen parts: the parties are divided into two groups, the Swiss (“on the one hand”) and the EU and its member states (“on the other”).