Grant v. Strong 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, William Grant, was held in a federal prison in California. Grant sought a writ of habeas corpus from the California Supreme Court, which was denied. Grant then appealed to the United States Supreme Court. The Supreme Court held that the California Supreme Court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the writ of habeas corpus was a federal prerogative, 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. In conclusion, the Supreme Court held that the California Supreme Court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the writ of habeas corpus was a federal prerogative, 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.

In Grant v. Strong, the Supreme Court was tasked with determining whether a contract between two parties could be enforced when it had been made without consideration and in violation of a state statute. The majority opinion held that the contract should not be enforced because it violated public policy as expressed by the state legislature through its enactment of a statute prohibiting such contracts. Justice Field dissented from this decision, arguing that while he agreed with the majority's conclusion regarding public policy considerations, he believed that there were other reasons why enforcement of this particular contract would not violate any law or public policy principle. He argued that since both parties to the agreement had acted in good faith and no fraud or misrepresentation was involved, then enforcing their agreement would not undermine any legal principles nor harm anyone else who might have an interest in either party's performance under it. Furthermore, Justice Field noted that if courts refused to enforce agreements simply because they lacked consideration or violated statutes then many innocent people may suffer unjustly due to unforeseen circumstances beyond their control which led them into making such agreements without proper foresight into potential consequences for doing so.