A collision of a truck and a car killed Thomas Smith (the truck driver), Donald Cionci (the car driver), and John Lynch (a car passenger). A third car passenger, John Harris, was injured. Edward Dutcher owned the car and had entrusted it to Cioni. Harris and Smith's estate sued Dutcher and the estates of Lynch and Cionci in a state court action. Lynch's administrator, Provident Tradesmens Bank (P), sued Cionci's estate and won a $50,000 settlement. That settlement was uncollectible. Dutcher had a $100,000 liability insurance policy on his auto with Lumbermen’s Mutual Casualty Co. (D). That policy included coverage for anyone driving the car with Dutcher's permission. D had declined to defend Cionci's estate in the P v. Cionci suit; Cionci was not covered by Dutcher's policy because his use exceeded the permission granted by Dutcher. P sued D in diversity for the $50,000 liquidated claim against Cionci's estates. Harris and Smith's estate were joined as plaintiffs. Dutcher was not joined, and that failure was not asserted by D at trial. All the plaintiffs were Pennsylvania residents. Dutcher was also a Pennsylvania resident. The district court found for the plaintiffs. The court of appeals reversed and dismissed the case; Dutcher was an indispensable party whose joinder would destroy diversity. The case had to be dismissed for the lack of subject matter jurisdiction. The Supreme Court granted certiorari.