In Hippolutus Joseph Augustine Estho et al. v. Benjamin L. Lear, Administrator of Thaddeus Kosciuszko, the Supreme Court was asked to decide whether a contract between two parties should be enforced even though it had been made in violation of a federal law prohibiting such contracts from being formed without congressional approval. The plaintiffs argued that they had entered into an agreement with Thaddeus Kosciuszko for the sale and transfer of certain lands in Louisiana before Congress passed legislation making such agreements illegal; therefore, they claimed their rights under the contract were still valid despite its illegality at the time it was created. The defendant countered that since Congress had prohibited these types of contracts after this one was made, it could not be enforced by any court or other authority within the United States government and thus must be declared void ab initio (from its inception). After considering both sides' arguments, the Supreme Court ultimately held that although Congress may have prohibited similar future transactions from taking place without its consent, this particular contract could not retroactively become invalid due to subsequent legislation and must therefore remain enforceable as written by both parties at its creation.

In Hippolutus Joseph Augustine Estho et al. v. Benjamin L. Lear, Administrator of Thaddeus Kosciuszko, the Supreme Court was tasked with determining whether a bequest made by General Thaddeus Kosciuszko to his friend Thomas Jefferson in 1798 constituted an absolute gift or if it was subject to certain conditions that had not been fulfilled at the time of his death in 1817. The majority opinion held that the bequest did constitute an absolute gift and therefore could not be revoked by any subsequent act on behalf of General Kosciuszko; however, Justice Story dissented from this ruling and argued that there were sufficient facts presented to suggest that General Kosciuszko intended for certain conditions to apply before Mr. Jefferson could receive full title over the property he had been gifted - namely, a requirement for him to use part of its proceeds towards emancipating slaves owned by himself or others within Virginia as well as providing funds for educating them after emancipation occurred - which would have rendered it revocable upon failure of these conditions being met prior to his death in 1817.