Prosecutions began soon after Congress enacted the Sherman law. These prosecutions were generally of two sorts:
- Prosecutors accused trade unions of violating the Sherman Act when they organized strikes and boycotts. Thus judges who were hostile to trade unions--a judicial hostility that was common in the 1890s and thereafter--ruled that unions were engaging in conspiracies in retraint of trade, and ordered them to stop their actions. These cases created an issue that extended well into the Progressive Era. Employers hostile to unions sought to strengthen the Sherman law as a union-busting instrument, while unions sought legislative language specifically exempting them from application of the antitrust laws.
- Prosecutors accused businesses of violating the law. In the first case to reach the Supreme Court, the E.C. Knight or Sugar Trust case, the Court ruled in 1895 against the government. Although the sugar trust controlled 98 per cent of the sugar refining capacity in the nation, the Court ruled that manufacturing was a local, not interstate, activity, and thus was beyond the purview of the federal government.
In general, before 1897 prosecutions against businesses were unsuccessful. After Theodore Roosevelt became President, there were renewed efforts to use the Sherman Act.