Peyton v. Heinekin was a case heard by the United States Supreme Court in 1871. The case involved a dispute between two parties over the ownership of a shipment of beer. The plaintiff, Peyton, was a brewer who had contracted with the defendant, Heinekin, to ship a large quantity of beer from New York to Virginia. Heinekin had agreed to pay for the shipment, but failed to do so. Peyton then sued Heinekin for the unpaid balance. The Supreme Court ruled in favor of Peyton, finding that Heinekin had breached the contract and was liable for the unpaid balance. The Court held that Heinekin was liable for the full amount of the contract, even though the beer had not been delivered. The Court reasoned that Heinekin had accepted the contract and was therefore obligated to pay for the shipment, regardless of whether the beer was delivered or not. The Court's decision in Peyton v. Heinekin established an important legal principle: that a party who has accepted a contract is liable for the full amount of the contract, even if the goods or services are not delivered. This principle has been applied in numerous cases since then, and is still an important part of contract law today.

In the case of Peyton v. Heinekin, Justice Field delivered a dissenting opinion in which he argued that the majority's decision was inconsistent with prior Supreme Court decisions and would lead to an unjust result. He noted that while it is true that a contract must be performed according to its terms, this does not mean that one party can unilaterally change those terms without consent from both parties. In this case, the defendant had agreed to pay for goods on delivery but then changed his mind after they were delivered and refused payment; as such, Justice Field believed it was unfair for him not to have been held liable for breach of contract. Furthermore, he argued that if contracts could be so easily avoided by simply changing one's mind after performance has already begun or completed then no business transactions would ever take place since there would be no guarantee of security or stability in any agreement made between two parties.