McLean v. Fleming was a United States Supreme Court case that dealt with the issue of whether a contract between two parties was valid. The case involved a contract between William McLean and John Fleming, in which McLean agreed to pay Fleming a certain amount of money for the use of a certain piece of land. The contract was signed by both parties, but McLean later refused to pay the money. Fleming then sued McLean for breach of contract. The Supreme Court held that the contract was valid and enforceable. The Court noted that the contract was signed by both parties and that there was no evidence that either party had been coerced into signing it. The Court also noted that the contract was not against public policy and that it was not unconscionable. Therefore, the Court held that the contract was valid and enforceable, and that McLean was liable for breach of contract.

Justice Field delivered the dissenting opinion in McLean v. Fleming, arguing that the majority's decision was incorrect and should be reversed. He argued that a contract between two parties is binding upon them both, regardless of whether it has been reduced to writing or not. The defendant had agreed to pay an amount for services rendered by the plaintiff, and thus he should have been held liable for payment even if there was no written agreement between them. Furthermore, Justice Field noted that while verbal contracts are generally difficult to prove due to lack of evidence, this case did not present such difficulty since witnesses were available who could testify as to what had transpired between the parties involved in this dispute. In conclusion, Justice Field believed that because there existed sufficient proof of a valid contract between these two parties which obligated one party (the defendant) to make payment for services provided by another (the plaintiff), then judgment should have gone in favor of the latter instead of being dismissed as it was by the majority opinion.