Jonna Lingle (plaintiff) was an employee for the Norge Division of Magic Chef, Inc. (Norge) (defendant). Lingle filed a worker’s compensation claim for an injury that she sustained in the course of her employment. A few days later, Norge terminated Lingle’s employment for filing a false worker’s compensation claim. Lingle’s union filed a grievance based on a collective-bargaining agreement that protected Lingle from being discharged without just or proper cause. The grievance was arbitrated, and the arbitrator found in favor of Lingle. Prior to the conclusion of the arbitration, Lingle sued Norge in the Illinois Circuit Court for Williamson County, alleging that she had been discharged in retaliation for her worker’s compensation claim. Norge removed the case to federal district court and moved to dismiss on the ground that the Labor Management Relations Act of 1947 (LMRA), 29 U.S.C. § 185(a), preempted Lingle’s state-tort claim of retaliatory discharge. The district court dismissed the complaint. The court of appeals affirmed. The United States Supreme Court granted certiorari.