In McCool v. Smith, the Supreme Court of the United States was asked to decide whether a state court had jurisdiction over a case involving an alleged breach of contract between two citizens from different states. The plaintiff, Mr. McCool, argued that since he and his defendant were both citizens of different states, the federal courts should have exclusive jurisdiction in this matter due to diversity among parties involved. However, the defendant argued that since there was no dispute as to which state's laws applied in this case and it did not involve any other federal questions or issues related to interstate commerce or foreign relations then it should be heard by a state court instead. Ultimately, after considering all arguments presented by both sides on appeal from lower courts' decisions regarding jurisdictional matters; the Supreme Court ruled in favor of Mr. Smith stating that because there were no disputes as to which law would apply and no other federal questions at issue here; then indeed it fell within proper scope for resolution by a State court rather than Federal one under existing legal precedents set forth at time when decision rendered back 1861 .

In the case of McCool v. Smith, the Supreme Court was asked to decide whether a contract between two parties that had been made in one state and then moved to another could be enforced by courts in both states. The majority opinion held that such contracts were not enforceable outside of the original state where they were created. However, Justice Curtis dissented from this decision, arguing that it would lead to confusion and uncertainty for those who enter into interstate contracts. He argued that if a contract is validly formed under one state's laws, then it should be given full faith and credit by other states as well - regardless of which jurisdiction has physical possession or control over any property involved in the agreement. Furthermore, he noted that Congress had already passed legislation providing for enforcement of such agreements across multiple jurisdictions; thus there was no need for judicial intervention on this matter at all.