In Flournoy v. Lastrapes, the United States Supreme Court was asked to decide whether a Louisiana state court had the authority to issue a writ of habeas corpus to a prisoner who had been convicted in a federal court. The petitioner, Flournoy, had been convicted in a federal court of a crime and sentenced to imprisonment. He then sought a writ of habeas corpus from the Louisiana state court, claiming that his conviction was unconstitutional. The Supreme Court held that the Louisiana state court did not have the authority to issue a writ of habeas corpus to a prisoner who had been convicted in a federal court. 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 court's judgment. The Court also noted that the writ of habeas corpus was a remedy for federal prisoners, and that the state court could not interfere with the federal court's judgment. In conclusion, the Supreme Court held that the Louisiana state court did not have the authority to issue a writ of habeas corpus to a prisoner who had been convicted in a federal court. 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 court's judgment.

In Flournoy v. Lastrapes, the Supreme Court was asked to decide whether a Louisiana state court had jurisdiction over a case involving two citizens of different states. The majority opinion held that the Louisiana court did have jurisdiction, but Justice Field dissented from this decision. He argued that under Article III of the Constitution, only federal courts could hear cases between citizens of different states and thus it was unconstitutional for the Louisiana court to do so. Furthermore, he noted that if state courts were allowed to take such cases then there would be no uniformity in how these disputes were resolved since each state has its own laws and procedures governing civil matters like this one. Finally, he concluded by stating that allowing state courts to adjudicate such controversies would lead to confusion and uncertainty as well as potential conflicts with decisions made by other jurisdictions on similar issues which could ultimately undermine public confidence in our judicial system.