Mulligan v. Corbins was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The case arose when a prisoner, Mulligan, was held in a federal prison in New York and sought a writ of habeas corpus from the state court. The state court granted the writ, and the federal government appealed the decision to the Supreme Court. The Supreme Court held that the state court did not have the authority to issue the writ of habeas corpus. The Court reasoned that the writ of habeas corpus was a federal power, and that the state court did not have the authority to interfere with the federal government's power to imprison individuals. The Court also noted that the writ of habeas corpus was a fundamental right, and that the state court should not be allowed to interfere with the federal government's power to imprison individuals. The Court's decision in Mulligan v. Corbins established that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The decision also established that the writ of habeas corpus was a fundamental right, and that the state court should not be allowed to interfere with the federal government's power to imprison individuals.

In Mulligan v. Corbins, the Supreme Court was tasked with deciding whether a contract between two parties could be enforced if it had been made in violation of state law. The majority opinion held that the contract was not enforceable because it violated state law and thus public policy. However, Justice Field dissented from this decision on the grounds that contracts should only be invalidated when they are "injurious to society or inconsistent with good morals." He argued that since there were no such considerations present in this case, then enforcing the contract would not harm anyone else and therefore should be allowed to stand as valid under common law principles of freedom of contract. Furthermore, he noted that denying enforcement would create an incentive for people to break their contractual obligations without consequence which could lead to further instability within society at large.