When the American Railway Union's 1894 boycott of Pullman cars paralyzed the western railroads, the federal government broke it with the new weapon of the labor injunction — a court order against the strike itself — enforced by 12,000 troops who left some thirty workers dead. Eugene Debs and the ARU leadership were imprisoned for six months at Woodstock, Illinois, not for any crime but for contempt of the injunction; the Supreme Court's In re Debs blessed the procedure, and "government by injunction" ruled labor relations for forty years.

Debs entered Woodstock a trade unionist and left it a socialist, reading his way to the politics that would later earn him the Espionage Act's ten-year sentence. The Pullman prisoners established the pattern of the era: the strike leader jailed by judicial decree, without jury, whenever labor won too much.