The United States Supreme Court case, United States Railroad Retirement Board v. Fritz, dealt with the constitutionality of amendments made to the Railroad Retirement Act in 1974. The amendments aimed at eliminating a dual-benefit scheme that allowed some railroad workers to receive both industry pensions and social security benefits. Three retired railroaders challenged these changes arguing they violated their Fifth Amendment due process rights by creating arbitrary classifications among beneficiaries. The Supreme Court disagreed and upheld the amendments in a 6-3 decision announced in 1980. It ruled that Congress had rational basis for its actions as it was trying to preserve financial stability of the pension system while treating all groups fairly during this transition period away from dual benefits.

In the dissenting opinion for United States Railroad Retirement Board v. Fritz, Justice Brennan argued that the majority's decision was inconsistent with previous rulings on equal protection under the Fifth Amendment. He believed that Congress' classification of railroad workers in this case was not rationally related to a legitimate government interest and thus violated their constitutional rights. The legislation at issue reduced benefits for some retired railroad employees but not others based on an arbitrary distinction - whether they had worked in the industry before or after 1936. Justice Brennan contended that there was no rational basis for this differentiation as it did not serve any discernible legislative purpose nor relate to fiscal responsibility as claimed by Congress. Instead, he saw it as a random cutback imposed only upon certain retirees without justification, which amounted to unconstitutional discrimination.