In the case of John Hancock Mutual Life Insurance Company v. Harris Trust and Savings Bank, the Supreme Court ruled in favor of Harris Trust. The issue at hand was whether a contract between an insurance company (John Hancock) and a pension plan's trustee (Harris Trust), which violated Employee Retirement Income Security Act (ERISA) provisions, could be considered void or if it should be enforced to protect innocent third parties. The court held that ERISA does not provide for equitable remedies such as reformation or surcharge against non-fiduciaries who participate in prohibited transactions; instead, they are subject to appropriate legal remedies including rescission of contracts made in violation of its terms. Therefore, even though John Hancock had acted improperly by entering into an illegal transaction with Sperry Corporation’s retirement fund managed by Harris Bank, the contract itself remained enforceable.

In the dissenting opinion for John Hancock Mutual Life Insurance Company v. Harris Trust and Savings Bank, Justice Scalia disagreed with the majority's interpretation of ERISA (Employee Retirement Income Security Act). He argued that it was not Congress' intent to make insurance companies fiduciaries under ERISA when they are merely following contractual obligations set out in an annuity contract. According to him, this would mean every insurer providing a guaranteed benefit policy would be considered a fiduciary under ERISA - an outcome he believed Congress did not intend. Furthermore, he criticized the majority’s reliance on Department of Labor regulations as definitive interpretations of statutory terms without considering whether those regulations were consistent with Congressional intent or even reasonable interpretations of the statute itself.