Andrew Aldridge and Others, Plaintiffs in Error, brought a case against Nathaniel F. Williams to the Supreme Court of the United States. The dispute was over an 1838 contract between Aldridge and Williams for the sale of slaves from Virginia to Mississippi. According to this contract, if any slave died before reaching their destination or became unfit for service due to age or infirmity during transit then Williams would be responsible for compensating Aldridge with another slave of equal value as replacement. However, when several slaves did not survive their journey across state lines, Williams refused payment on grounds that he had no knowledge that such deaths were possible at time of purchase and thus should not be held liable under terms agreed upon by both parties in good faith. The Supreme Court ultimately ruled in favor of Andrew Aldridge and his co-plaintiffs; they found that since it is common knowledge among those who deal with slavery transactions that death may occur during transportation due to various causes beyond control - even though there was no specific clause outlining such risks within original agreement - therefore Nathaniel F. William's refusal constituted breach of contract which required him pay compensation accordingly according to its terms regardless whether he foresaw potential losses beforehand or not .

In the case of Andrew Aldridge and Others v. Nathaniel F. Williams, the Supreme Court was tasked with determining whether a contract between two parties could be enforced when it had been made in violation of an existing state law. The majority opinion held that such contracts were not enforceable, but Justice McLean dissented from this decision on the grounds that enforcing these contracts would not violate public policy or any other principle of justice and equity. He argued that if a contract is validly formed by competent parties who are both aware of its terms, then it should be upheld regardless of whether it violates some preexisting statute or regulation; otherwise, individuals would have no assurance as to their contractual rights and obligations since they could always be superseded by subsequent laws passed by legislatures. Furthermore, he noted that allowing courts to invalidate contracts based on violations against statutes may lead to unjust results where one party has already performed under the agreement while another has reaped all its benefits without consequence due solely to a change in legislation after-the-fact.