In County of Ralls v. Douglass, the Supreme Court of the United States was asked to decide whether a county could be held liable for damages caused by a defective bridge. The plaintiff, Douglass, had been injured when his horse and wagon fell through a bridge that had been built by the county. The county argued that it was not liable for the damages because it had not been negligent in constructing the bridge. The Supreme Court held that the county was liable for the damages caused by the bridge. The Court reasoned that the county had a duty to maintain the bridge in a safe condition, and that it had breached this duty by failing to inspect the bridge and repair any defects. The Court also held that the county was liable for the damages even though it had not been negligent in constructing the bridge. The Court's decision established that a county can be held liable for damages caused by a defective bridge, even if the county was not negligent in constructing the bridge. This decision has been cited in numerous cases since then, and has been used to establish the principle that a county can be held liable for damages caused by a defective bridge.

In the case of County of Ralls v. Douglass, Justice Field delivered a dissenting opinion in which he argued that the Court should have granted relief to the plaintiff on equitable grounds. He asserted that although it was true that there had been no formal deed executed for the land in question, this did not mean that an agreement between parties could not be enforced by equity. In his view, when two parties agree upon a certain exchange and one party has already performed their part of the bargain while expecting performance from the other side, then justice requires enforcement of such an agreement even without any written document or deed being present. Furthermore, Justice Field noted how both sides had acted as if they were bound by contract and thus felt compelled to uphold what he believed was a valid agreement between them despite its lack of formality.