Delaware County Commissioners v. Diebold Safe and Lock Company was a case heard by the Supreme Court of the United States in 1895. The case involved a dispute between the Delaware County Commissioners and the Diebold Safe and Lock Company over the installation of a safe in the county courthouse. The Commissioners had contracted with Diebold to install the safe, but the company failed to do so in a timely manner. The Commissioners then sought to recover damages from Diebold for the delay. The Supreme Court held that the Commissioners were entitled to recover damages from Diebold for the delay in installing the safe. The Court found that the Commissioners had a valid contract with Diebold and that the company had breached the contract by failing to install the safe in a timely manner. The Court also held that the Commissioners were entitled to recover damages for the delay, as the delay had caused them to suffer a financial loss. The Court's decision in this case established the principle that a party who breaches a contract is liable for any damages caused by the breach. This principle has been applied in numerous cases since then, and it remains an important part of contract law today.

In the Supreme Court case of Delaware County Commissioners v. Diebold Safe and Lock Company, Justice Holmes delivered a dissenting opinion. He argued that the majority’s decision was wrong because it failed to consider whether or not there had been any fraud committed by Diebold in its contract with Delaware County. According to Holmes, if there had been fraud then the county would have grounds for rescission of their agreement with Diebold and should be allowed to recover damages from them accordingly. Furthermore, he argued that even if no fraud had occurred, it did not necessarily follow that the county could not rescind their contract on other legal grounds such as mistake or misrepresentation; thus they should still be able to seek redress from Diebold regardless of whether or not actual fraudulent behavior took place. In conclusion, Justice Holmes believed that since this issue was never addressed by either party during trial proceedings nor considered by the majority in their ruling, further investigation into these matters were necessary before a final judgment could be made regarding liability for breach of contract between Delaware County and Diebold Safe & Lock Company