The main purpose of this legislation is to prevent the International Criminal Court (ICC) from using United Nations facilities located in the United States, particularly in New York City. The bill aims to establish a formal agreement that would restrict the ICC's access to these facilities, reflecting the U.S. government's stance on the court's jurisdiction and authority. Key provisions of the legislation include a requirement for the U.S. Ambassador to the United Nations to initiate negotiations for a supplemental agreement to the existing United Nations Headquarters Agreement.