In the 1998 case Humana Inc., et al. v. Mary Forsyth et al., the Supreme Court ruled on a dispute involving health insurance coverage and federal jurisdiction over state law claims. The plaintiffs, policyholders of Humana Health Insurance, filed a class action lawsuit against Humana and its subsidiary for alleged violations of Nevada's Deceptive Trade Practices Act (DTPA). They claimed that the companies had fraudulently concealed their practice of receiving significant discounts from healthcare providers without passing those savings onto policyholders. The defendants sought to remove this case to federal court under the Employee Retirement Income Security Act (ERISA), arguing that it preempted state law claims because they related to an employee benefit plan. However, both district and appellate courts rejected this argument, holding that ERISA did not completely preempt DTPA as it applied in this context. Upon review by the Supreme Court, it was held in favor of Forsyth with a unanimous decision stating that while ERISA does have broad preemption powers over state laws relating to any employee benefit plan; however, these do not extend so far as to include all actions dealing indirectly with such plans or where potential remedies may duplicate ERISA’s civil enforcement provisions.

In the dissenting opinion for Humana Inc., et al. v. Mary Forsyth et al., Justice Stephen Breyer argued that the majority's decision to allow RICO claims in this case would open up a floodgate of litigation, potentially overwhelming federal courts with cases better suited for state-level adjudication. He expressed concern over the broad interpretation of "racketeering activity," which he believed could encompass ordinary business disputes and lead to an explosion of RICO suits against businesses engaged in no more than common commercial disagreements or negotiations. Furthermore, he disagreed with applying punitive treble damages under RICO to routine contractual disputes between private parties, arguing it was not Congress’s intent when enacting the law. Instead, Justice Breyer suggested that such issues should be resolved through traditional contract law remedies at state level rather than invoking federal racketeering laws designed primarily to combat organized crime.