In the case of Oxford Health Plans LLC v. John Ivan Sutter, the U.S. Supreme Court was asked to decide whether an arbitrator had overstepped his authority by allowing a class action suit to proceed in arbitration, despite there being no explicit provision for class arbitration in the contract between Oxford Health Plans and Dr. Sutter. The dispute began when Dr. Sutter filed a lawsuit against Oxford on behalf of himself and other physicians alleging that they were underpaid by Oxford's health insurance plan due to its faulty claims review system. The court ruled unanimously in favor of upholding the arbitrator’s decision, stating that as long as an arbitrator is interpreting a contract—even if he or she does so erroneously—their decision stands unless it can be shown they strayed from their delegated task of interpreting said agreement. This ruling reinforced previous decisions emphasizing deference towards arbitral decisions and limited judicial review power over them.

In the dissenting opinion for Oxford Health Plans LLC v. John Ivan Sutter, Justice Alito, joined by Justice Thomas and Chief Justice Roberts, argued that the arbitrator's decision to allow class arbitration was fundamentally flawed because it did not respect the parties' agreement. They contended that while an arbitrator may interpret contracts based on their understanding of contractual law or policies, they must ultimately adhere to what both parties have agreed upon in their contract. In this case, they believed that there was no clear evidence showing that both Oxford Health Plans and Sutter had agreed to class arbitration when signing their contract. Therefore allowing such a procedure would be overstepping boundaries set by the Federal Arbitration Act (FAA). The justices also expressed concern about how class arbitration could potentially undermine individual rights as well as increase costs and complexities without providing any substantial benefits compared to traditional bilateral arbitration.