Amy v. Dubuque is a United States Supreme Court case that was decided in 1878. The case involved a dispute between the plaintiff, Amy, and the defendant, Dubuque. Amy had purchased a tract of land from Dubuque, and the deed included a clause that stated that the land was to be held in trust for Amy's benefit. However, Dubuque had failed to register the deed with the county recorder, and as a result, the land was sold to another party. Amy sued Dubuque for breach of contract, arguing that Dubuque had failed to fulfill its obligation to register the deed. The Supreme Court held that Amy was entitled to recover damages from Dubuque for its breach of contract. The Court reasoned that the deed was valid and enforceable, and that Dubuque had a duty to register the deed in order to protect Amy's interests. The Court also held that Amy was entitled to recover damages for the loss of the land, as well as for the costs of litigation. In conclusion, the Supreme Court held that Amy was entitled to recover damages from Dubuque for its breach of contract. The Court reasoned that Dubuque had a duty to register the deed in order to protect Amy's interests, and that Amy was entitled to recover damages for the loss of the land, as well as for the costs of litigation.

Justice Field delivered the dissenting opinion in Amy v. Dubuque, arguing that the majority had erred in their interpretation of a contract between two parties. He argued that while it was true that there were ambiguities present within the language of the contract, these should be interpreted as having been intended to benefit both parties equally and not just one party over another. Furthermore, he stated that if either party wished to take advantage of any ambiguity or uncertainty contained within a contract then they must prove such an intention by clear and convincing evidence which neither side had done here. As such, Justice Field concluded his dissent by stating that no court could properly interpret this ambiguous language without proof from either side as to what their intentions were when entering into said agreement and thus he would have reversed the decision made by lower courts on this matter.