Whether the Due Process Clause permits California to exercise personal jurisdiction over a nonresident personally served while voluntarily and temporarily present in the State, when the suit is unrelated to his forum activities.
Holding
Yes. Personal service on Burnham during his voluntary physical presence in California constitutionally supported California's jurisdiction over him.
Reasoning
Justice Scalia's plurality opinion treated in-state personal service, often called transient jurisdiction or "tag" jurisdiction, as one of the most deeply rooted and continuously accepted bases of personal jurisdiction in American law. At the time the Fourteenth Amendment was adopted, courts widely recognized that a state could exercise jurisdiction over a person found and personally served within its borders, even if the person's visit was brief and the claim arose elsewhere.
The plurality concluded that this settled and continuing tradition itself satisfies the International Shoe formulation of due process: jurisdiction must comport with "traditional notions of fair play and substantial justice." Physical presence was the historical touchstone from which modern minimum-contacts doctrine developed, so it would be backwards to use that doctrine to invalidate jurisdiction based on the very physical presence it was designed to supplement.
The Court therefore affirmed without requiring California to show that Burnham had continuous and systematic contacts with the State or that the divorce litigation arose from his California conduct. Burnham voluntarily entered California and was properly served there; under the longstanding rule, that was enough.