In the case of American Express Co. v. Koerner (1980), the Supreme Court dealt with a dispute over whether or not an arbitration clause in a contract could be enforced when one party claimed that it was fraudulently induced into signing the agreement. The court ruled in favor of American Express, stating that any claims regarding fraudulent inducement should be decided by an arbitrator rather than a court, as per the terms of their contract's arbitration clause. This decision reinforced and clarified previous rulings on similar issues, establishing firmly that questions about contractual validity are for arbitrators to decide if such provision is included within contracts.

The dissenting opinion in the case of American Express Co. v. Koerner argued that the majority's decision to dismiss the case was premature and potentially harmful to future cases involving similar issues. The dissent, led by Justice Brennan, contended that there were significant factual disputes which should have been addressed at trial rather than being dismissed outright by summary judgment. They believed that these unresolved questions could have a substantial impact on whether or not American Express had violated antitrust laws as alleged by Koerner. Furthermore, they expressed concern over how this ruling might set a precedent for other courts to prematurely dismiss complex cases without fully examining all relevant facts and evidence.