Treat v. Jemison 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 a prisoner, William Treat, was held in federal custody in the state of Georgia. Treat sought a writ of habeas corpus from the state court, which the court granted. The United States government then 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 a prisoner. 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 a prisoner.

In Treat v. Jemison, the United States 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 a third state. The majority opinion held that it did not have such jurisdiction and dismissed the case. Justice Field, however, dissented from this decision and argued that under Article III of the Constitution, states are empowered to exercise judicial power over citizens residing within their borders regardless of where they were originally domiciled or what their citizenship status is at any given time. He further noted that if this interpretation were adopted then it would be necessary for every suit between two citizens of different states to be tried in either federal courts or those located within both parties' respective home states - something he felt was impractical and unnecessary given existing legal precedent on similar matters.