Spatz & Company and River Park, Inc. (plaintiffs) wanted to develop 162 acres of land in the City of Highland Park (the City) (defendant). The plaintiffs petitioned the City for a change in the zoning ordinance and approval of the development plans. In 1989, the City approved, pending the filing of the final engineering plans. The plaintiffs alleged that the City then purposefully delayed issuing the final approvals in order to force the plaintiffs into foreclosure so the City could buy the property at below market value. In 1993, the plaintiffs sued the City in the United States District Court for the Northern District of Illinois under 42 U.S.C. § 1983 for violations of their constitutional due process rights. The court held that the plaintiffs had failed to demonstrate that their due process rights were violated and dismissed the complaint with prejudice. The plaintiffs appealed to the United States Court of Appeals for the Seventh Circuit, but the dismissal was affirmed. In 1994, the plaintiffs sued in Illinois circuit court for “(1) tortious interference with a business expectancy, (2) breach of an implied contract, and (3) abuse of governmental power.” The remaining counts were dismissed. The plaintiffs requested $50 million in compensatory and punitive damages. The City moved to dismiss the lawsuit on the ground that it was barred by res judicata. The trial court granted the motion. The appellate court overturned the dismissal, because the claims asserted in the state court were different than those asserted in the federal suit. The City appealed to the Supreme Court of Illinois.