The classes are all treaties under international law; They differ only in the domestic law of the United States. See the article on the Bricker Amendment for the history of the relationship between treaty powers and constitutional provisions. In rare cases, such as Ethiopia and Qing Dynasty China, local governments were 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] The end of the preamble and the beginning of the agreement itself are often indicated by the words „agreed as follows“. The signing of a treaty implies that the signing of a treaty implies recognition, that the other party is a sovereign State and that the envisaged agreement is applicable under international law. Therefore, nations can be very cautious when it comes to qualifying an agreement as a treaty. For example, in the United States, agreements between the United States are pacts and agreements between states and the federal government or between government authorities are declarations of intent. According to the preamble to the Treaty Act, treaties are a source of international law.
In the event of a conviction of an act or the absence of an act under international law, the act will not take on international legality, even if it is authorized by domestic law.  This means that in the event of a conflict with domestic law, international law always takes precedence. Despite the relative ease of executive agreements, the president still often chooses to follow the formal contractual process of an executive agreement in order to gain congressional support on issues that require Congress to pass implementing legislation or appropriate means, as well as agreements that impose complex long-term legal obligations on the United States. For example, the agreement of the United States, Iran and other countries is not a treaty.