In the United States, the term “treaty” has a different, more limited legal meaning than in international law. U.S. legislation distinguishes what it calls “treaties” from “executive agreements” that are either “executive agreements of Congress” or “single executive agreements.” Classes are all treatises of international law in the same way; they differ only in U.S. domestic law. When a state limits its contractual obligations by reservations, other contracting states have the opportunity to accept, contradict or contradict these reserves. If the state accepts (or does not act at all), both the reserve state and the accepting state are exempt from the legal obligation reserved with respect to their legal obligations with each other (the acceptance of the reservation does not alter the legal obligations of the accepting state with respect to the other contracting parties). If the state objects, the parts of the contract concerned by the booking are completely cancelled and no longer create legal obligations for the reserve and acceptance of the state, again only with regard to the other. Finally, if the state opposes and opposes it, there are no legal obligations arising from this treaty between these two states. The resisting and reticating state essentially refuses to recognize the reserving state, is even a party to the treaty.
 In rare cases, as with Ethiopia and the Qing Dynasty in China, local governments have been able to use treaties to at least mitigate the effects of European colonization. These included learning the intricacies of European diplomatic customs and using treaties to prevent the power from overstepping its agreement or opposing different powers. [Citation required] An essential part of treaty drafting is that the signing of a treaty implies recognition, that the other party is a sovereign state and that the agreement, considered to be under international law, is applicable. Therefore, nations can be very cautious when it comes to qualifying a treaty agreement. In the United States, for example, interstate agreements are pacts and agreements between states and the federal government or between government authorities are statements of intent. 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.
The language of treaties, such as that of a law or contract, must be interpreted if the text does not appear clear or if it is not immediately clear how it should be applied in a perhaps unforeseen circumstance. The Vienna Convention stipulates that treaties must be interpreted in “good faith” according to “the ordinary meaning given to the contractual terms in context and in light of their purpose and purpose.” International legal experts also often invoke the “principle of the greatest possible effectiveness,” which interprets the language of the treaty so that it has the maximum strength and effectiveness in defining obligations between the parties. The Constitution does not have a supremacy clause with the same effects as those of the U.S. Constitution, which interests the debate on the relationship between treaties and the laws of the states of Brazil. There are three ways to change an existing treaty. First, a formal change requires that States Parties be forced to go through the ratification process again. The renegotiation of the treaty provisions can be long and time-consuming and often some parties to the original treaty will not become parties to the amended treaty.