Morgan's Executor v. Gay was a case heard by the United States Supreme Court in 1874. The case involved a dispute between the executor of a deceased man's estate and the man's widow. The executor argued that the widow was not entitled to a portion of the estate, as the deceased had made a will that excluded her from any inheritance. The widow argued that the will was invalid, as it had been made under duress. The Supreme Court ultimately sided with the widow, ruling that the will was invalid due to the fact that it had been made under duress. The Court held that a will made under duress was not valid, and that the widow was entitled to a portion of the estate. This ruling established a precedent that a will made under duress is not valid, and that the rights of the parties involved must be respected.

In Morgan's Executor v. Gay, the Supreme Court was tasked with determining whether a contract between two parties that had been partially performed should be enforced by a court of law. The majority opinion held that because the contract had not been fully executed, it could not be enforced in court and thus dismissed the case. However, Justice Field dissented from this decision and argued that partial performance of an agreement can still create legal obligations for both parties involved. He reasoned that if one party has already completed their part of the bargain then they are entitled to receive what is due to them under the terms of said agreement regardless if all parts have yet to be fulfilled or not. Furthermore, he noted how such contracts were often used as security for loans which would make it difficult for lenders to recoup their money without enforcing these agreements even when only partially performed.