Plaintiff, the United States, brought an action in the U.S. District Court for the Southern District of New York against the Palestine Liberation Organization (PLO) and four individuals seeking an injunction to close the PLO’s Permanent Observer Mission (Mission) to the United Nations as violative of the Anti-Terrorism Act of 1987 (ATA). The district court (per Palmieri, J.) entered summary judgment for defendants and held: (1) the ATA does not require the closure of the PLO’s Mission to the United Nations; (2) the status of the PLO’s Mission, an invitee of the United Nations, is protected by the Agreement Between the United States and the United Nations Regarding the Headquarters of the United Nations (Headquarters Agreement); and (3) Congress did not intend the ATA to supersede the Headquarters Agreement.