“It is, of course, true that even treaties with foreign nations are carefully interpreted not to depart from the authority and jurisdiction of the states of that nation, unless it is clearly necessary to conduct national policy. . . . But state law must yield if it is incompatible or contrary to the policy or provisions of a treaty or an international pact or agreement. Second, the power of a state to refuse the application of rights on the basis of foreign law, which runs counter to the public policies of the Forum. must give way to higher federal policy, which is underpinned by a treaty, an international pact or an agreement. The British government system is a monarchy. In this case, the position of head of state is different from that of head of government. The Queen is not only head of state, but commander-in-chief of the armed forces, while the Prime Minister is the head of government. In the presidential system of government, as practiced in the United States, the president is the head of state and the head of government.
The U.S. Constitution does not explicitly give a president the power to enter into executive agreements. However, it may be authorized to do so by Congress or may do so on the basis of its foreign relations management authority. Despite questions about the constitutionality of executive agreements, the Supreme Court ruled in 1937 that they had the same force as treaties. As executive agreements are made on the authority of the president-in-office, they do not necessarily bind his successors. Diplomacy is the art and practice of negotiation between representatives of groups or states. It generally refers to international diplomacy, the organization of international relations through the intercession of professional diplomats in the organization of peace, trade, war, economics, culture, the environment and human rights. International treaties are usually negotiated by diplomats before being approved by national politicians. In an informal or social sense, diplomacy is the use of tact to obtain strategic benefits or to find mutually acceptable solutions to a common challenge, a number of instruments being the formulation of statements in a non-confrontational or polite manner.
So it`s about the head of state against the head of government. However, you can continue to read for more information on the subject. The President of the United States of America is the Head of State and Government of the United States.