Intentional misconduct frequently has extraterritorial consequences. Terrorist attacks, toxic pollution, civil rights violations, and other intentional torts can cause harm within a state despite originating outside the state. Those harms raise a vexing constitutional question: when do the local effects of intentional wrongdoing authorize personal jurisdiction over a defendant whose conduct occurred outside the forum? The answer has several significant implications. Granting or denying jurisdiction can support or undermine regulatory interests by allocating power between states, imposes burdens on the parties that can impede access to justice, and alters risk assessments that shape both socially desirable and socially destructive behavior.