Ex parte Waples is 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 a prisoner, Waples, was held in federal custody in the state of Texas. Waples sought a writ of habeas corpus from the state court, claiming that he was being held in violation of the Constitution. 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 federal custody. 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 detain prisoners. 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 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 authority to interfere with the federal government's power to detain prisoners. 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 protect this right.

In Ex Parte Waples, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving an alleged violation of federal law. The majority opinion held that the state court did not have such jurisdiction and thus could not hear the case. However, Justice Field dissented from this decision, arguing that it was within Congress' power to grant states authority to enforce federal laws in their own courts. He argued further that if Congress chose to do so, then there would be no constitutional impediment preventing them from doing so; therefore, he concluded that it should be up to Congress alone as opposed for the Court itself determine whether or not states can exercise jurisdiction over cases involving violations of federal law.