An agreement between Congress and the executive branch is reached in different ways. Congress may authorize the President to enter into an agreement already negotiated, such as when a multilateral agreement creates an international organization such as the International Monetary Fund. Congress has sometimes approved presidential agreements through legislation or the use of funds to fulfill its obligations. The Supreme Court of the United States, in united states v. Pink (1942), considered that international executive agreements that have been concluded in force have the same legal status as treaties and do not require the approval of the Senate. In Reid v. Covert (1957), while reaffirming the President`s ability to enter into executive agreements, he decided that such agreements could not be contrary to federal law or the Constitution in force. A treaty is an international agreement concluded in writing between two or more sovereign States and subject to international law, whether enshrined in a single legal act or in two or more related instruments. Treaties have many names: conventions, agreements, alliances, pacts, charters and statutes, among others. The choice of name has no legal significance. Contracts generally fall into one of two broad categories: bilateral (between two countries) and multilateral (between three or more countries). Presidents have also invoked the power to unilaterally withdraw from agreements between Congress and the executive, but there is an emerging scientific debate about the extent to which the Constitution allows the president to act in such circumstances without the consent of the legislature. .