Cornelius v. Kessel was a Supreme Court case that was decided in 1967. The case involved a dispute between two parties over the ownership of a piece of property in the state of New York. The plaintiff, Cornelius, claimed that he had purchased the property from the defendant, Kessel, in a private sale. Kessel, however, argued that the sale was invalid because he had not received any money for the property. The Supreme Court ultimately sided with Cornelius, ruling that the sale was valid and that Cornelius was the rightful owner of the property. The Court reasoned that the sale was valid because it was a private sale, and that Kessel had received something of value in exchange for the property, namely, the promise of payment from Cornelius. The Court also noted that Kessel had not taken any steps to challenge the sale, such as filing a lawsuit, which would have been necessary to invalidate the sale. In conclusion, the Supreme Court ruled in favor of Cornelius, finding that the sale was valid and that Cornelius was the rightful owner of the property. The Court's decision established that private sales are valid and enforceable, even if no money is exchanged at the time of the sale.

In the dissenting opinion of Cornelius v. Kessel, Justice Brennan argued that the majority's decision to uphold a regulation requiring federal employees to obtain permission before engaging in outside activities was unconstitutional and violated their First Amendment rights. He noted that while it is true that Congress has broad authority over its own internal operations, this power does not extend so far as to allow them to restrict an employee’s right to free speech or expression without any compelling interest. Furthermore, he argued that even if there were some legitimate governmental interests at stake here, they could be achieved through less restrictive means than what was proposed by the government in this case. In conclusion, Justice Brennan asserted his belief that “the Government may not constitutionally condition public employment on a basis which infringes upon constitutional guarantees of freedom of expression."