Collins v. Riley was a United States Supreme Court case that addressed the issue of whether a state court had the authority to issue a writ of habeas corpus to a prisoner who was being held in a federal prison. The case arose when a prisoner, Collins, was held in a federal prison in Massachusetts. Collins sought a writ of habeas corpus from the state court, arguing that he was being held in violation of his constitutional rights. 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 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 remedy, 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 remedy for violations of federal law, and that the state court did not have the authority to interfere with the federal government's enforcement of federal law. The Court's decision in Collins v. Riley established that state courts do not have the authority to issue writs of habeas corpus to prisoners held in federal prisons. The decision also established that the writ of habeas corpus is a federal remedy, and that state courts do not have the authority to interfere with the federal government's power to imprison individuals.

Justice Field delivered the dissenting opinion in Collins v. Riley, arguing that the court should not have reversed the decision of the Supreme Court of California. He argued that under California law, a party who had been served with notice of an action could be held liable for costs even if they were found to be non-suable due to lack of jurisdiction over them or their property. Justice Field believed this was a reasonable interpretation and application of state law and therefore he disagreed with reversing it on appeal. Furthermore, he noted that there was no federal statute which contradicted this interpretation and thus it should stand as valid state law without interference from federal courts. In conclusion, Justice Field felt strongly that since there was no conflict between state and federal laws in this case, then any ruling by a higher court would constitute an unwarranted intrusion into matters traditionally left up to states' discretion.