Due process permits a state court to impose a personal obligation on a nonresident only when the defendant has sufficient forum contacts that suit there accords with traditional notions of fair play and substantial justice. The inquiry is practical rather than mechanical: the Court must consider the quality and nature of the defendant’s activities, as well as relevant interests of the forum and plaintiff.
Kulko’s two brief California military stopovers, occurring roughly 13 years before the dispute, could not support jurisdiction over an unrelated later action. Nor could the fact that the parties married in California, because they were New York domiciliaries who thereafter spent their married life in New York. The original custody arrangement also did not create jurisdiction merely because it required the children to visit their mother in whatever state she chose to live in; treating visitation as a contact would discourage reasonable family arrangements and make jurisdiction depend on a custodial parent’s unilateral location choices.
Kulko did not purposefully avail himself of California law by accepting his daughter’s wish to live with her mother and purchasing her plane ticket. His accommodation was a parental response aimed at family harmony, not an effort to conduct activity, obtain benefits, or invoke legal protections in California. Services such as schools, police, hospitals, and recreation primarily benefited the child, not Kulko, and were not benefits he deliberately sought for himself.
The asserted financial benefit from the daughter’s absence from Kulko’s New York home likewise did not establish a California contact. Any reduced household expense resulted from her leaving his home, not from her presence in California. More fundamentally, this argument confused Kulko’s possible substantive obligation to provide additional support with the distinct jurisdictional question of which state could fairly adjudicate that obligation. New York, where Kulko lived and where the agreement was negotiated, had unquestioned personal jurisdiction over him.
California’s effects theory did not justify jurisdiction. That doctrine generally concerns out-of-state wrongful conduct causing injury within the forum or commercial activity deliberately affecting forum residents. Kulko neither inflicted injury in California nor conducted commercial activity there; the dispute arose from a New York marital separation and a support agreement negotiated in New York, with virtually no connection to California.
Fairness considerations strongly favored New York. Kulko had remained in the marital domicile, while Horn had moved across the country. His single act of permitting his daughter to live with her mother was not conduct from which a reasonable parent should anticipate the burden of litigating a support case 3,000 miles away. Making jurisdiction turn on whether he bought the ticket rather than tried unsuccessfully to prevent the move would impose an unjustified burden on family relations.
California had an important interest in protecting children residing within its borders, but that interest did not itself make California a fair forum for a nonresident parent with no meaningful relevant contacts. California and New York both participated in reciprocal-support procedures that allowed Horn to initiate a claim in California while having its merits adjudicated in New York, where jurisdiction over Kulko could be obtained. Those procedures reduced the practical hardship of requiring litigation in the obligor’s home state.