The U.S. Supreme Court case Connolly et al., Trustees of the Operating Engineers Pension Trust v. Pension Benefit Guaranty Corporation et al., 1985, revolved around a dispute over the Multiemployer Pension Plan Amendments Act (MPPAA) of 1980. The MPPAA required employers withdrawing from pension plans to pay a fixed and certain debt to cover their share of unfunded vested benefits in order to protect employees' pensions. The plaintiffs, trustees of a multi-employer pension plan, argued that this provision constituted an unconstitutional taking without just compensation under the Fifth Amendment's Takings Clause because it imposed retroactive liability on them for obligations they had not agreed upon when joining the plan. However, the Supreme Court disagreed with this argument and upheld MPPAA’s constitutionality by ruling that while it did impose new liabilities on employers based on past actions, these were within Congress's power as part of its efforts to regulate economic transactions and ensure financial stability in private pension systems. It was also noted that although there may be some impact on contractual relationships due to such legislation changes; however, these do not necessarily constitute takings requiring compensation.

In the dissenting opinion for Connolly et al., Trustees of the Operating Engineers Pension Trust v. Pension Benefit Guaranty Corporation et al., Justice O'Connor argued that the Multiemployer Pension Plan Amendments Act (MPPAA) violated due process rights under the Fifth Amendment. She contended that imposing retroactive liability on employers withdrawing from a pension plan was fundamentally unfair and arbitrary, as it did not take into account whether an employer had contributed to any funding deficiency or if they were even aware of potential liabilities when joining a multi-employer pension plan. Furthermore, she disagreed with majority's assertion that MPPAA served a legitimate legislative purpose by preventing financial instability in such plans, arguing instead that Congress could have achieved this goal through less drastic means without infringing upon constitutional rights.