Rather than the executive or legislative branches, it was the judiciary that proved perhaps the most conservative institution of the Progressive Era, frequently stymieing Progressive reform efforts. By the 1880s, the Supreme Court had radically redefined the Fourteenth Amendment, which had been ratified in 1868 to empower the federal government to overturn state laws that violated citizens' rights. Originally passed by Republicans in Congress to protect the newly emancipated African-Americans of the South, by the 1880s, the Fourteenth Amendment was more often cited by the Court as the basis for defense of the "liberty of contract."45 The Fourteenth Amendment decreed that "No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law." The Court interpreted "persons" to include corporations and thus accorded incorporated businesses all the rights of real human citizens. State laws that established maximum work hours or mandated safe working conditions were invalidated, since the judiciary interpreted such reforms as violations of a citizen's right to make contracts. The concept of "liberty of contract," then, was the idea that any legislation intending to help workers could be ruled unconstitutional because it supposedly actually harmed those workers by taking away their freedom to work long hours for low wages in poor working conditions. This powerful legal interpretation profoundly influenced the Justices' reasoning, and as a result, their decisions directly affected the rights and liberties (or lack thereof) that the government could guarantee to American workers.
The judiciary wielded significant power over Progressive reforms, since it could invalidate or reinterpret important legislation with a simple majority ruling. The Court could reject carefully written laws that congressmen and state legislatures had spent months pushing through. Initially, the Court was willing to uphold legislation that regulated companies with a significant "public interest." In Munn v. Illinois (1875), the Court ruled that the state of Illinois was constitutionally authorized to establish a board that set maximum charges and worked to prevent railroad rate discrimination. But in 1886, the Court reversed itself and declared in Wabash v. Illinois that only the federal government could regulate railroads that were engaged in interstate commerce.46 It also narrowly interpreted anti-monopoly legislation like the Sherman Antitrust Act of 1890; five years after its passage, the Court ruled that the government could not dissolve the E.C. Knight sugar refining monopoly because the Constitution only gave Congress the power to regulate trade and not manufacturing.
Not only did the court impede enforcement of such legislation, but it also hampered workers' rights by applying its new interpretation of the Fourteenth Amendment and the "freedom of trade" concept to cases involving labor strikes. In the Danbury Hatters' Case of 1908, the Court decided in favor of a non-union hat manufacturer in Danbury, Connecticut. It held that the hatter's union violated the Sherman Antitrust Act by unlawfully combining to restrain trade. Such cases indicated some of the unintended consequences (and interpretations) of antitrust legislation like the Sherman Act; and they set precedents for judicial interference with organized labor. The Sherman Act was intended to prevent business combinations that would restrain trade, but instead justices used it as grounds for issuing injunctions against worker strikes on the grounds that they "illegally interfered with the freedom of trade," as historian Eric Foner47 put it. Thus, even when the Court did not invalidate laws, its reinterpretation of them could prompt equally dramatic results. Congress could pass legislation that the judges applied to workers, when it was intended to regulate businesses. Such unforeseen implications made the quest for reform all the more tortuous and complicated.
In a series of invalidations and re-interpretations, the Supreme Court undid many of the key victories that Progressives had won in Congress, thereby forcing Progressive legislators to reassess their approach. The Wabash ruling on interstate commerce prompted the creation of the Interstate Commerce Commission in 1887. Yet the Court continued to side in favor of the railroads almost every time that the ICC brought suit against them.48 Even on the state level, the New York Court of Appeals declared unconstitutional a state law that forbade cigar manufacture in tenements (rundown, low-rent apartments in the inner-city) because such regulation deprived cigar manufacturers of the freedom to "choose" their place of work. In Illinois, an 1895 decision invalidated a state law that outlawed garment production in sweatshops and set a forty-eight hour maximum work-week for women and children. The Illinois State Supreme Court argued that this law infringed on workers' economic "liberty," regardless of their gender or age.49 Similarly, the Supreme Court voided a New York state law that established a maximum 60-hour workweek (or ten-hour-day) for bakers on the grounds that such maximum work hour laws interfered with the right of contract between employer and employee. A Kansas law forbidding "yellow-dog contracts" (which mandated that workers not belong to any union before joining the company) was declared unconstitutional as a violation of "personal liberty." The Court also declared that states could not mandate against coal companies paying their miners in scrip that was only usable at company stores, rather than actual paper currency.50
In 1916, Woodrow Wilson signed the Keating-Owen Act, which fought child labor by making it illegal for companies to ship goods produced by children across state lines. But two years later, the Court declared the act unconstitutional in Hammer v. Dagenhart on the grounds that it employed federal control of interstate commerce for noncommercial objectives and that it interfered with the states' police powers. The Court had allowed states to regulate child labor within their borders, but it took a more restrictive approach to laws concerning the conditions of adult female workers, because it considered such regulations to be violations of adult employees' freedom of contract. Yet this tradition reversed itself in 1908, when the Court upheld Oregon's ten-hour workday maximum for women in Muller v. Oregon. Jurist Louis D. Brandeis submitted a 112-page brief for the state that mobilized a range of economic, historical, sociological, and medical evidence to prove that overworked women presented a risk to public health, safety, and welfare. This seemingly persuasive argument—given the amount of contemporary pseudo-science behind it—convinced the usually conservative Court. The justices decided in favor of labor legislation for women on the grounds that "as healthy mothers are essential to vigorous offspring, the physical wellbeing of woman becomes an object of public interest and care in order to preserve the strength and vigor of the race."51
Progressives welcomed this decision, and it seemed on the surface to represent a victory for working women everywhere. Yet, in another paradox representative of the contradictions that plagued Progressivism, the Muller decision actually portended some negative consequences for women in America. Because of the restrictions on their workday, women could not get jobs that required long hours. They were even further marginalized to low-paying and marginal labor. Additionally, this Court-approved differentiation of men and women would later become an object of feminist criticism, since it connoted government sanction of the notion that the sexes were not equal and instead possessed inherent differences—for women, these were considered deficiencies. Such differences could be used to explain everything from pay discrepancies between genders to the fact that women were considered "too emotional" to vote.52 The Court changed course once again in 1923 with the Adkins v. Children's Hospital case in which it struck down a Washington D.C. law from 1918 that guaranteed working women and children a minimum wage in the district. In the decision, Justice Sutherland recognized that individuals did not possess an absolute freedom to make contracts, but that the District of Columbia law was an unconstitutional "price-fixing" measure that violated citizens' Fifth Amendment right to life, liberty, and property.53 In either case, working women and children faced restricted job opportunities because of their limited hours or the "freedom" to work long hours with little regulation of any kind. Such a double bind exemplified the difficulties of enacting true labor reform in the United States.