Master Lochner-era decision striking down a state ban on employer "yellow-dog" contracts as an unconstitutional interference with liberty of contract under the Fourteenth Amendment. with this comprehensive case brief.
Coppage v. Kansas is a hallmark of the Lochner era's robust protection of economic liberty—specifically, the so-called liberty of contract—under the Fourteenth Amendment's Due Process Clause. Decided in 1915, the case invalidated a Kansas criminal statute that prohibited employers from conditioning employment on an agreement that the employee would not join a labor union (a "yellow-dog" contract). Leaning heavily on its earlier decision in Adair v. United States, the Supreme Court concluded that the state's attempt to bar these agreements arbitrarily intruded on the private freedom of employers and employees to set the terms of their employment relationship.
For law students, Coppage illuminates both the doctrinal commitments and the practical limits of the Lochner-era jurisprudence. It shows how the Court once conceptualized the police power: as permitting regulations tied to health, safety, morals, or direct public welfare, but not authorizing legislation aimed merely at equalizing bargaining power or pursuing general social or economic policy ends. The case also sets the stage for the later New Deal constitutional transformation, under which the liberty-of-contract framework receded and robust labor protections—through statutes like the Norris-LaGuardia Act and the National Labor Relations Act—were sustained by a deferential approach to economic regulation.
Coppage v. Kansas, 236 U.S. 1 (1915) (U.S. Supreme Court)
Kansas enacted a criminal statute making it unlawful for an employer to require, as a condition of hiring or continued employment, that an employee agree not to join or to withdraw from a labor union (a "yellow-dog" contract). Coppage, a managerial agent of a private employer, insisted that an employee agree not to join a union; when the employee refused, he was discharged. Coppage was prosecuted and convicted under the Kansas statute. The Kansas Supreme Court affirmed the conviction, upholding the statute as a valid exercise of the state's police power to protect workers' freedom of association and to prevent coercion in employment contracts. Coppage sought review in the U.S. Supreme Court, arguing that the statute violated the Due Process Clause of the Fourteenth Amendment by impermissibly interfering with the liberty of employers and employees to contract for the terms of employment.
Does a state statute criminalizing employer–employee agreements that condition employment on an employee's promise not to join a labor union violate the liberty of contract protected by the Fourteenth Amendment's Due Process Clause?
Under the Fourteenth Amendment's Due Process Clause, a state may not arbitrarily interfere with the liberty of contract by prohibiting employer–employee agreements regarding conditions of employment unless the regulation bears a real and substantial relation to legitimate ends of the police power (such as the protection of public health, safety, or morals). Legislation aimed merely at equalizing bargaining power or conferring special advantages on one class of private parties, without a sufficient connection to those traditional police-power ends, is unconstitutional.
Yes. The Kansas statute is unconstitutional because it arbitrarily interferes with the liberty of contract of employers and employees, in violation of the Fourteenth Amendment's Due Process Clause.
The Court, relying on Adair v. United States, reasoned that both employers and employees possess a constitutional liberty to contract about the terms of employment, including agreements concerning union membership. The state's police power, while broad, does not authorize criminalizing private agreements that do not implicate public health, safety, or morals and that concern matters of purely private concern. The statute effectively compelled employers to accept union membership as compatible with the employment relation, thus depriving them of a legitimate term they might otherwise insist upon and criminalizing their attempt to make such a term part of the bargain. The majority characterized the law as class legislation designed to advantage unions and employees by restricting employers' freedom, rather than as a measure tailored to a legitimate public interest. It rejected the notion that the state could pursue a generalized policy of reducing inequalities in bargaining power by coercively reallocating rights in private agreements. In the Court's view, the employer's right to discharge at will and to set conditions for employment, and the employee's reciprocal right to refuse those conditions, were core aspects of economic liberty. Because the statute's asserted purposes fell outside the traditional scope of the police power and bore no sufficient relation to public health, safety, or morals, the law violated due process. Dissenting opinions (notably by Justice Holmes and others) argued that there is no absolute liberty of contract, that employment relations are marked by disparities in bargaining power, and that the state may reasonably regulate to protect freedom of association and prevent coercion. The dissents viewed the statute as a permissible, non-arbitrary means of addressing a real social problem and as consistent with the state's broad authority over economic relations.
Coppage is a canonical Lochner-era case that entrenched the liberty-of-contract doctrine and limited state efforts to police labor relations, particularly regarding unionization. It, together with Adair, sanctioned yellow-dog contracts against state and federal interference. The decision's approach to substantive due process was later repudiated during the New Deal constitutional shift: West Coast Hotel Co. v. Parrish (1937) disavowed Lochner's strict scrutiny of economic regulation, and NLRB v. Jones & Laughlin Steel Corp. (1937) upheld federal protections for union organizing. Statutorily, the Norris-LaGuardia Act (1932) curtailed federal court enforcement of yellow-dog contracts, and the National Labor Relations Act (1935) affirmatively protected collective activity. While Coppage was not overruled in a single opinion, its core doctrine is no longer good law, serving today primarily as a teaching tool for understanding the rise and fall of liberty-of-contract jurisprudence and the evolution of labor and constitutional law.
A yellow-dog contract is an agreement in which an employee promises, as a condition of hiring or continued employment, not to join or to withdraw from a labor union. In Coppage, Kansas criminalized employers' use of such agreements. The Supreme Court held that criminalizing these contracts impermissibly interfered with the liberty of contract protected by the Fourteenth Amendment.
Adair struck down a federal statute that prohibited yellow-dog contracts in the railroad industry, reasoning that it violated the liberty of contract (and exceeded Congress's commerce power as then understood). Coppage extended that reasoning to state law, concluding that a state's criminal ban on yellow-dog contracts likewise violated due process. Together, they formed a Lochner-era barrier to legislative efforts protecting unionization.
Not on its core holding. The Lochner-era liberty-of-contract doctrine was repudiated by cases such as West Coast Hotel Co. v. Parrish (1937), which adopted a deferential approach to economic regulation. Subsequent decisions, including NLRB v. Jones & Laughlin Steel (1937), upheld comprehensive labor protections. Statutes like the Norris-LaGuardia Act (1932) and the NLRA (1935) rendered yellow-dog agreements unenforceable and protected collective activity. Today, Coppage survives mainly as historical precedent illustrating the pre–New Deal constitutional order.
The decision principally rested on the Fourteenth Amendment's Due Process Clause and the liberty-of-contract doctrine. While the majority criticized the law as class legislation favoring one set of private parties (union members and employees) over another (employers), its analysis was framed as an arbitrary interference with liberty rather than as a distinct Equal Protection holding.
Use Coppage to illustrate the Lochner-era test: regulations that merely redistribute bargaining power or adjust private economic relations, without a close nexus to health, safety, or morals, were struck down as arbitrary interferences with liberty of contract. Then contrast with the post–1937 framework, where courts apply rational basis review to economic regulation and routinely uphold labor laws like the NLRA. Coppage is also useful for discussing the shift from judicial skepticism of economic regulation to deference to legislative judgments about social and economic policy.
Coppage v. Kansas encapsulates the high-water mark of the Lochner-era commitment to liberty of contract and its skepticism toward state efforts to recalibrate bargaining power in labor markets. By invalidating a criminal ban on yellow-dog agreements, the Court drew a sharp line around the police power, confining it to traditional categories like health, safety, and morals and rejecting redistributive or associational protections as illegitimate ends.
The New Deal transformation rendered Coppage's core premise obsolete, as courts embraced legislative capacity to regulate labor relations and protect collective action. For modern students, Coppage is less a source of binding doctrine than a critical waypoint in constitutional development—illuminating how theories of due process, labor policy, and judicial role have shifted across American constitutional history.
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