John McCollum, the plaintiff in error, brought a case against Jenison Eager to the Supreme Court. The dispute was over an alleged breach of contract between them. According to McCollum's complaint, he had agreed to sell and convey certain lands located in Michigan Territory for $1,000; however, Eager failed to pay him as promised. As such, McCollum sought damages from Eager for his failure to fulfill their agreement. In its ruling on this case, the Supreme Court held that there was sufficient evidence presented by both parties which showed that a valid contract existed between them and that it had been breached by Eager when he failed to make payment according to its terms. Therefore they found in favor of McCollum and awarded him damages accordingly. This decision established important legal precedent regarding contracts made within territories prior their admission into statehood or union with other states at the time of formation of those agreements

In the case of John McCollum v. Jenison Eager, Justice McLean wrote a dissenting opinion in which he argued that the plaintiff had not been given due process under the law. He noted that there was no evidence presented to prove any contract between the parties and thus no basis for recovery on either side. Furthermore, he stated that even if such a contract did exist, it would have been voidable because of its uncertain terms and lack of consideration from both sides. Additionally, Justice McLean argued that since this was an action at law rather than equity, damages should be awarded only when they are certain and definite; otherwise it is impossible to determine what amount should be paid by each party as compensation for their respective losses or injuries suffered. Finally, he concluded by stating his belief that courts must always adhere strictly to legal principles in order to ensure justice is served fairly and equitably among all parties involved in litigation proceedings.