The U.S. Supreme Court case Anderson et al. v. Mt. Clemens Pottery Co., 1945, revolved around the issue of whether time spent by employees in activities before and after their regular working hours should be considered as compensable work time under the Fair Labor Standards Act (FLSA). The plaintiffs were employees at Mt. Clemens Pottery Company who argued that they should be paid for the additional time spent walking to their workstations and preparing for work, which was not included in their standard pay calculations. The court ruled in favor of the workers, stating that these preliminary activities constituted "work" within the meaning of FLSA and thus required compensation from employers. This decision established a new precedent known as "portal-to-portal" pay where all tasks performed by an employee during his or her daily duties are deemed payable even if they do not directly contribute to production output.

In the dissenting opinion for Anderson et al. v. Mt. Clemens Pottery Co., Justice Frankfurter argued that the majority's decision was an overreach of judicial power, as it effectively rewrote legislation rather than interpreted it. He contended that Congress had not intended to include preliminary activities such as walking to workstations within compensable working time when drafting the Fair Labor Standards Act (FLSA). Instead, he believed these were incidental activities and should be considered part of 'waiting time', which is explicitly excluded from FLSA coverage. Furthermore, he disagreed with the majority's use of a de minimis rule in determining what constitutes trivial amounts of work beyond regular hours; instead arguing this should be determined on a case-by-case basis by lower courts using common sense and fairness principles.