In Shepley et al. v. Cowan et al., the Supreme Court of the United States was asked to decide whether a contract between two parties was valid and enforceable. The contract in question was between Shepley and Cowan, and it stated that Cowan would pay Shepley a certain amount of money in exchange for the transfer of certain real estate. The Supreme Court held that the contract was valid and enforceable. The Court noted that the contract was clear and unambiguous, and that both parties had agreed to its terms. Furthermore, the Court found that the contract was supported by consideration, meaning that both parties had given something of value in exchange for the other's promise. The Court also held that the contract was not voidable due to any lack of capacity on the part of either party. The Court noted that both parties were of sound mind and had the capacity to enter into a contract. Finally, the Court held that the contract was not voidable due to any fraud or misrepresentation on the part of either party. The Court found that there was no evidence of any fraud or misrepresentation on the part of either party. In conclusion, the Supreme Court held that the contract between Shepley and Cowan was valid and enforceable.

In Shepley et al. v. Cowan et al., the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving land titles in Missouri that were originally granted by the United States government prior to Missouri's admission into the Union. The majority opinion held that since Congress had not expressly authorized such suits, and since there was no federal law providing for them, then it must be assumed that they are within the exclusive jurisdiction of state courts. Justice Field dissented from this decision on two grounds: firstly, he argued that under Article III of the Constitution, all cases arising under laws passed by Congress should be heard in federal courts; secondly, he argued that even if this did not apply in this particular instance due to lack of congressional authorization or specific statutory provision for such suits, then it would still fall within "the general supervisory power" given to federal courts over matters concerning title and possession of lands granted by Congress before states' admission into union - which is implied from other constitutional provisions and has been recognized as valid precedent throughout American history.