From Withdrawal from International Agreements: Legal Framework, the Paris Agreement, and the Iran Nuclear Agreement (February 9, 2017 R44761):
The legal procedure through which the United States withdraws from treaties and other international agreements has been the subject of long-standing debate between the legislative and executive branches. Recently, questions concerning the role of Congress in the withdrawal process have arisen in response to statements made by President Donald J. Trump that he may consider withdrawing the United States from certain high-profile international commitments. This report outlines the legal framework for withdrawal from international agreements under domestic and international law, and it examines legal issues related to the potential termination of two agreements that may be of significance to the 115th Congress: the Paris Agreement on climate change and the Joint Comprehensive Plan of Action (JCPOA) related to Iran’s nuclear program.
Although the Constitution sets forth a definite procedure whereby the Executive has the power to make treaties with the advice and consent of the Senate, it is silent as to how treaties may be terminated. Moreover, not all agreements between the United States and foreign states are made through Senate-approved, ratified treaties. The President also enters into executive agreements, which do not receive the Senate’s advice and consent, and “political commitments,” which are not binding under domestic or international law. The legal procedure for withdrawal often depends on the type of agreement at issue, and the process may be further complicated when Congress has enacted legislation implementing the agreement into domestic law.