Ex parte Hoard 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 petitioner, Hoard, was a prisoner in the custody of the United States Marshal for the District of Columbia. He had been convicted of a crime in the District of Columbia and was serving his sentence in the federal prison. Hoard sought a writ of habeas corpus from the Supreme Court of the District of Columbia, claiming that his conviction was unconstitutional. The Supreme Court of the District of Columbia granted the writ, and the United States Marshal brought Hoard before the court. The United States Attorney then filed a motion to quash the writ, arguing that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in federal custody. The Supreme Court of the District of Columbia denied the motion, and the United States appealed to the Supreme Court of the United States. The Supreme Court of the United States 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 remedy, and that the state court did not have the power to interfere with the federal government's power to enforce its laws. The Court also noted that the writ of habeas corpus was a remedy of last resort, and that the prisoner should have sought relief from the federal courts first. The Court thus reversed the decision of the Supreme Court of the District of Columbia and quashed the writ of habeas corpus.

In Ex Parte Hoard, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by a non-resident against another non-resident. The majority opinion held that the state court did not have jurisdiction in this case because it lacked personal jurisdiction over either party. However, Justice Field dissented from this decision and argued that the state court should be allowed to exercise its power of general jurisdiction when both parties are non-residents. He reasoned that since neither party resided within the boundaries of the forum's territory or were served with process there, they could not challenge any judgment rendered by such courts on jurisdictional grounds. Furthermore, he argued that allowing states to exercise their powers of general jurisdiction would help ensure uniformity among different jurisdictions and promote justice for all litigants regardless of where they reside or do business.