Flanders v. Tweed 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 a federal prison. The case arose when a prisoner, Flanders, was held in a federal prison in New York and sought a writ of habeas corpus from the state court. The state court issued the writ, but the federal government argued that the state court did not have the authority to do so. The Supreme Court ultimately held that the state court did not have the authority to issue the writ of habeas corpus. The Court reasoned that the writ of habeas corpus was a federal power, 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 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 a federal prison. The Court reasoned that the writ of habeas corpus was a federal power, and that the state court should not be allowed to interfere with the federal government's power to protect this right.

In Flanders v. Tweed, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by a citizen of one state against another in which the defendant resided in yet another state. The majority opinion held that it did not have such jurisdiction, and Justice Field dissented from this decision. He argued that under Article III of the Constitution, Congress has given federal courts exclusive original jurisdiction over all cases between citizens of different states; thus, he reasoned that if Congress intended for there to be concurrent or supplemental jurisdiction with respect to these types of cases then they would have provided for it explicitly within their legislation. Furthermore, he noted that since no such provision exists then any attempt by a State court to exercise authority over matters involving citizens from other States is unconstitutional and should be struck down as void ab initio (from its inception).