New York State Conference of Blue Cross and Blue Shield Plans v. Travelers Insurance Co.

New York required hospitals to add surcharges to bills for patients covered by certain commercial insurers and HMOs, but exempted Blue Cross and Blue Shield plans, which tended to pay hospitals faster and covered more people. Commercial insurers administering ERISA-governed plans sued state officials, arguing ERISA's express preemption clause invalidated the surcharge scheme; Blue Cross and Blue Shield entities (defendants) intervened to defend the law, and HMOs (plaintiffs) intervened on the insurers' side. The district court and court of appeals both ruled for the plaintiffs, finding preemption, and the defendants appealed.