Last month, the US Supreme Court issued a little-noticed order in a blockbuster case that, in the course of its 16-year history, has rocked foreign policy circles, upset the constitutional balance between Congress and the Courts, and so far, left American victims of terrorist attacks without relief.The case, Sokolow v. PLO, has its roots in the bloody years of the Second Intifada – a terror wave of suicide bombings, rocket attacks and sniper fire that killed more than a thousand Israelis and dozens of Americans. In the aftermath of the carnage, American victims and their families sued the Palestine Liberation Organization and Palestinian Authority under the Anti-Terrorism Act. The victims initially won a significant monetary judgment at trial, only to lose it when an appellate court reversed in 2016. The case has reached the US Supreme Court, where the justices have now overturned the appellate court’s decision and instructed that court to revisit the case in light of new amendments to the Anti-Terrorism Act. Congress had passed the Anti-Terrorism Act in 1992, after an elderly wheelchair-bound Jewish man, Leon Klinghoffer, was shot, killed and thrown off a ship by Palestinian terrorists. The law was explicitly designed to allow American citizens who are victims of terrorist attacks abroad to sue the perpetrators in US courts.After a decade of litigation, a Manhattan jury found the PA and PLO responsible for knowingly supporting six terrorist attacks in which Americans were killed and injured. The jury awarded damages to the families, resulting in a $655.5 million judgment.In 2016, however, a Second Circuit appellate court vacated the judgment. Invoking a complex legal doctrine known as “personal jurisdiction,” the Second Circuit explained that US courts lacked the authority to hear cases against terrorists who murder Americans on foreign soil, rendering the Anti-Terrorism Act toothless.Congress, however, has pushed back. With large bipartisan majorities, Congress has enacted two amendments to close the technical loopholes the courts opened. Until now, however, the courts have not acquiesced. With April 27’s Supreme Court order, that may be about to change.Judicial hesitation to give full effect to Congress’ anti-terrorism legislation stems from an understandable, if misplaced, source. Responsible judges harbor an impulse to avoid issuing judgments with far-reaching foreign policy consequences. As Justice Ruth Bader Ginsburg explained in an opinion often cited by courts declining to enforce the Anti-Terrorism Act, there are “risks to international comity” when US courts venture abroad, and expansive US jurisdiction has “impeded negotiations of international agreements.”Allowing this hesitation to override the clear will of Congress, however, rests on a series of constitutional and policy mistakes. First, personal jurisdiction, as originally understood, is a doctrine of American federalism concerning the allocation of judicial power between the states. For this reason, a California court cannot assert power over a New Yorker who has no ties to California because doing so would infringe upon New York’s sovereignty. This understanding was eventually constitutionalized through the 14th Amendment’s Due Process Clause, which places restrictions upon the states. But the Anti-Terrorism Act is a federal statute invoking the power of the US over foreign entities. The Second Circuit misapplies a doctrine about inter-state federalism to a case about international relations.Second, courts can and should apply a presumption against the extraterritorial application of US law. This presumption captures legitimate concerns about international comity and potential blowback against US entities in foreign courts. But it is one thing to avoid interpretations of an ambiguous law that would apply it to events abroad; it is quite another to eviscerate a law’s explicit application to conduct that, in the words of the Anti-Terrorism Act, “occur[s] primarily outside” the US. Congress members decided that American victims should be allowed to sue supporters of international terrorism. That was their call.Last month, the Supreme Court implicitly recognized this fundamental truth. It instructed the Second Circuit to revisit its ruling in Sokolow in light of a recently enacted amendment to the Anti-Terrorism Act. In December, Congress passed the Promoting Security and Justice for Victims of Terrorism Act of 2019. The act subjects to the authority of US courts any entity that offers monetary rewards to those who commit terrorist attacks that kill Americans.Lawmakers have looked with increasing disgust at the PA “pay-for-slay” program, codified in Palestinian law, of providing monthly salaries to those convicted of terrorist attacks. In 2018, Congress passed the Taylor Force Act, which cut off US economic aid to the PA until it ceases its terrorist payment programs. Now, through its most recent amendment to the Anti-Terrorism Act, Congress has again shone a spotlight on the PA’s unjustifiably pro-terrorist policy.In Sokolow, the Second Circuit concluded its opinion overturning the jury award by acknowledging that “[t]he terror machine gun attacks and suicide bombings that triggered this suit and victimized these plaintiffs were unquestionably horrific.” With the Supreme Court’s instruction to revisit the case, the families can again hold onto the hope that the court will finally give them justice.Sander Gerber is CEO of Hudson Bay Capital Management. He is a distinguished fellow at the Jewish Institute for National Security of America and a fellow at the Jerusalem Center for Public Affairs. Ezra Husney is a student at Yale Law School and a former legal clerk to the Supreme Court of Israel.