Ex parte Boyer & Another 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 federal custody. The case arose when two prisoners, Boyer and another, were held in federal custody in the state of California. The state court issued a writ of habeas corpus to the federal authorities, ordering them to produce the prisoners in court. The federal authorities refused to comply, arguing that the state court did not have the authority to issue such a writ. 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 federal custody. The Court reasoned that the writ of habeas corpus was a federal prerogative, and that the state court did not have the power to interfere with the federal government's authority in this matter. The Court also noted that the writ of habeas corpus was a fundamental right, and that the federal government had the exclusive power to protect this right. In conclusion, 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 federal custody. The Court reasoned that the writ of habeas corpus was a federal prerogative, and that the state court did not have the power to interfere with the federal government's authority in this matter.

In Ex Parte Boyer & Another, the Supreme Court was asked to decide whether a writ of habeas corpus should be granted in order for two individuals to be released from prison. The majority opinion held that the writ should not be issued because it would interfere with the power of Congress and state legislatures to determine how prisoners are treated. Justice Field dissented, arguing that while Congress has authority over federal prisons, states have exclusive jurisdiction over their own prisons and thus must comply with constitutional requirements when imprisoning citizens. He argued that if an individual is being unlawfully detained by a state government then they can seek relief through habeas corpus as provided by Article I Section 9 of the Constitution. Furthermore, he noted that even though Congress may pass laws regarding imprisonment procedures within its borders, those laws cannot override or supersede any rights guaranteed under the Constitution. Therefore, Justice Field concluded that since these two individuals were being unlawfully imprisoned without due process they had every right to petition for release via habeas corpus and thus their request should have been granted by the court