From the summary of International Law and Agreements: Their Effect upon U.S. Law (RL32528, Sept. 19, 2018):
The status of an international agreement within the United States depends on a variety of factors. Self-executing treaties have a status equal to federal statute, superior to U.S. state law, and inferior to the Constitution. Depending upon the nature of executive agreements, they may or may not have a status equal to federal statute. In any case, self-executing executive agreements have a status that is superior to U.S. state law and inferior to the Constitution. Courts generally have understood treaties and executive agreements that are not self-executing generally to have limited status domestically; rather, the legislation
or regulations implementing these agreements are controlling.