In Killian v. Clark, the United States Supreme Court addressed the issue of whether a state court could enforce a contract that was made in violation of a state statute. The case involved a contract between two parties, Killian and Clark, in which Killian agreed to pay Clark a certain amount of money for the sale of a piece of property. The contract was made in violation of a state statute that prohibited the sale of property without a license. The state court had enforced the contract, and Killian appealed the decision to the Supreme Court. The Supreme Court held that the state court had the authority to enforce the contract, despite the fact that it was made in violation of the state statute. The Court reasoned that the state statute was not intended to invalidate contracts, but rather to regulate the sale of property. The Court also noted that the state statute did not provide for any penalty for violating the statute, and thus the contract was not void. The Court concluded that the state court had the authority to enforce the contract, and affirmed the decision of the lower court.

In Killian v. Clark, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving an administrator of an estate in another state. The majority opinion held that the state court did have jurisdiction and could proceed with its decision on the matter. However, Justice Field dissented from this opinion and argued that it would be unconstitutional for a state court to exercise authority over matters outside of its own borders. He reasoned that such action would violate both Article IV Section 1 of the Constitution which states "Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State" as well as Article III Section 2 which grants Congress power to make laws regulating interstate commerce. Furthermore he noted that allowing one state's courts to interfere with proceedings taking place in another would create confusion among citizens who may not know what laws apply where or how they should act when faced with conflicting legal decisions between two different states.