Webber v. Sobba

Webber (plaintiff) and Sobba (defendant) were injured in a car accident after drinking together, with Sobba driving and claiming Webber's physical advances caused her to lose control; Webber sued for negligence in federal court under diversity jurisdiction, and Sobba raised joint-enterprise as a defense, which Webber argued Arkansas law did not permit between members of the same joint enterprise. The district court denied Webber's summary judgment motion on that defense, instructed the jury it could find for Sobba on a joint-enterprise theory, and the jury found for Sobba; Webber appealed.

Whether, when interpreting an unsettled question of state law, a federal court should apply the rule it believes the state's highest court would adopt.