The U.S. Supreme Court case American Telephone and Telegraph Company v. Central Office Telephone, Inc., 1997 revolved around a dispute between AT&T and Central Office Telephone (COT) over the interpretation of their contract for long-distance telephone services. COT claimed that AT&T had breached its contractual obligations by charging rates higher than those agreed upon in the contract, while AT&T argued that it was entitled to charge these rates under federal tariff laws which superseded any conflicting agreements in private contracts. The court ruled in favor of COT, stating that federal law did not preempt private contractual arrangements unless explicitly stated otherwise by Congress or if there is clear evidence showing such intent from lawmakers' side. Therefore, even though tariffs filed with Federal Communications Commission generally have force of law, they do not necessarily override specific terms set out within individual service agreements.

In the dissenting opinion for American Telephone and Telegraph Company v. Central Office Telephone, Inc., Justice Ginsburg disagreed with the majority's interpretation of the 1970 amendment to §203(a) of the Communications Act. She argued that this amendment was intended to prevent a telephone company from discriminating against its competitors by charging them higher rates than it charged its own customers, not to allow a customer who had negotiated lower rates in good faith to sue for damages if those rates were later found unreasonable. Furthermore, she contended that allowing such suits would discourage companies from negotiating rate agreements at all, which would undermine one of Congress's main goals when it passed the Communications Act: promoting competition in telecommunications markets through negotiation rather than regulation.