Supreme Court Guts Clayton Act Labor Protections in Duplex Printing Decision

The Supreme Court rules 6-3 in Duplex Printing Press Co. v. Deering that the Clayton Act’s supposed protections for labor organizing do not prevent federal courts from enjoining union boycotts. Justice Mahlon Pitney holds that Section 20 of the Clayton Act, which labor had celebrated in 1914 as its “Magna Carta,” applies only to disputes between employer and immediate employees, not to broader solidarity actions by workers at other companies or in other cities. The decision effectively nullifies Congress’s intent to exempt labor from antitrust prosecution, returning unions to the legal vulnerability that had prevailed before the Clayton Act’s passage.

The case arises from the International Association of Machinists’ campaign against Duplex Printing, a Michigan manufacturer that paid below-union wages and refused to recognize the union. After organizing Duplex workers proved difficult, the union called for boycotts by machinists at companies using Duplex presses, asking members to refuse to install, repair, or service the machines. This secondary boycott strategy represented labor’s primary weapon for extending union standards across an industry. Lower courts had denied Duplex’s request for injunction based on Clayton Act protections, but the Supreme Court reverses, holding that the Act protects only direct employer-employee disputes.

Justice Louis Brandeis writes a powerful dissent joined by Justices Oliver Wendell Holmes and John Clarke, arguing that the majority “unduly limits the meaning of the words ’employer and employees’” and ignores the Clayton Act’s clear purpose to protect labor organizing from injunction. Brandeis notes that employers freely combine in trade associations and coordinate pricing without antitrust liability, while workers face prosecution for collective action. The Duplex decision, combined with similar rulings like Truax v. Corrigan (1921) and Bedford Cut Stone (1927), demonstrates how the Supreme Court systematically weaponized antitrust law against labor while exempting corporate combinations, maintaining the legal asymmetry that the Clayton Act was specifically designed to remedy.