Stuart v. Gay was a United States Supreme Court case that addressed the issue of whether a state court could issue a writ of habeas corpus to a prisoner who was being held in a federal prison. The case arose when a prisoner, William Stuart, was held in a federal prison in Massachusetts. Stuart 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 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 a federal prison. The Court reasoned that the writ of habeas corpus was a federal prerogative, and that the state court did not have the power to interfere with the federal government's authority 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 exercise of its power. 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 prerogative, and that the state court did not have the power to interfere with the federal government's authority 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 exercise of its power.

Justice Field delivered the dissenting opinion in Stuart v. Gay, arguing that the majority's decision was wrongfully decided and should be reversed. He argued that a contract for personal services is not assignable unless it contains an express provision allowing assignment or there is evidence of a custom permitting such assignments. In this case, he found no evidence of either an express agreement to allow assignment or any custom which would permit it; therefore, he concluded that the contract between Mr. Stuart and his employer could not be assigned by him to another party without violating its terms and conditions. Furthermore, Justice Field noted that even if there had been some form of authorization from Mr. Stuart’s employer to transfer his employment rights to someone else, those rights were still subject to termination at will by either party as provided under common law principles applicable in Massachusetts where the contract originated from - thus making any attempted transfer void ab initio (from inception). As such, Justice Field believed that since no valid transfer occurred here then Mr. Gay was never legally entitled to receive wages due under the original employment agreement with Mr. Stuart’s former employer; hence why he dissented against affirming judgment for plaintiff below on appeal before Supreme Court