What are agreements between states and the federal government called within the United States?
One significant part of treaty making is that signing a treaty implies recognition that the other side is a sovereign state and that the agreement being considered is enforceable under international law. Hence, nations can be very careful about terming an agreement to be a treaty. For example, within the United States, agreements between states are compacts and agreements between states and the federal government or between agencies of the government are memoranda of understanding.