In the case of United States v. Diebold, Incorporated in 1961, the U.S. Supreme Court ruled that a summary judgment is inappropriate when there are any material factual disputes between parties involved in a lawsuit. The government had sued Diebold for alleged violations of antitrust laws related to its acquisition of another company, Herring-Hall-Marvin Safe Co., arguing it would reduce competition and create a monopoly in the safe manufacturing industry. The District Court granted summary judgment to Diebold based on affidavits provided by both sides which were conflicting about whether or not this merger would indeed stifle competition. However, upon appeal by the government, the Supreme Court reversed this decision stating that if any doubt exists regarding material facts (in this case - potential impact on market competition), then it should be resolved at trial rather than through summary judgement.

The dissenting opinion in the United States v. Diebold, Incorporated case argued that there was not enough evidence to support a summary judgment against Diebold. The dissenters believed that the lower court had erred by failing to consider all of the facts and circumstances surrounding the case before making its decision. They contended that while some of Diebold's actions may have appeared suspicious or questionable, they were not necessarily indicative of an illegal conspiracy as alleged by the government. Furthermore, they pointed out inconsistencies and contradictions within the government's own arguments which further cast doubt on their claims against Diebold. Therefore, these justices felt it would be more appropriate for this complex matter to be fully explored during a trial rather than prematurely decided through summary judgment.