In the case of Miller v. Wilson, Sheriff of Riverside County, State of California (1914), the U.S. Supreme Court was tasked with determining whether a state law that regulated working hours violated an individual's right to contract freely under the Fourteenth Amendment. The plaintiff, Mr. Miller, argued that his employer had been unjustly penalized for allowing him to work more than eight hours in a day - something he willingly agreed to do and which did not harm public health or safety. However, the court ruled against him stating that it is within a state's power to regulate labor conditions and protect workers from exploitation by setting maximum working hours even if both parties agree otherwise voluntarily. This decision upheld California’s Eight Hour Law as constitutional because it served legitimate interests in protecting employees' health and welfare.

In the dissenting opinion for Miller v. Wilson, Justice Holmes argued that the California law in question, which limited women's working hours to eight per day and forty-eight per week, was not a violation of the Fourteenth Amendment’s Equal Protection Clause. He asserted that it was within a state's rights to regulate labor conditions based on sex due to inherent physiological differences between men and women. The majority had ruled this law as discriminatory towards female employees by limiting their freedom of contract under equal protection grounds; however, Holmes contended such regulations were justified given potential health risks associated with long work hours for women specifically. He believed these laws aimed at protecting public welfare rather than promoting gender discrimination.