United States v. Singer is a United States Supreme Court case that dealt with the issue of whether a federal court had the power to issue a writ of habeas corpus to a state prisoner. The case involved a man named John Singer, who was convicted of murder in the state of Pennsylvania and sentenced to death. Singer filed a petition for a writ of habeas corpus in the federal court, arguing that his conviction was unconstitutional. The federal court granted the writ, and the state of Pennsylvania appealed to the Supreme Court. The Supreme Court held that the federal court did not have the power to issue a writ of habeas corpus to a state prisoner. The Court reasoned that the writ of habeas corpus was a remedy that was available only to federal prisoners, and that the federal court did not have the power to interfere with the state's criminal justice system. The Court also noted that the writ of habeas corpus was a remedy that was available only in cases where the prisoner had been denied due process of law. In the end, the Supreme Court reversed the decision of the federal court and held that the writ of habeas corpus was not available to a state prisoner. The Court also noted that the writ of habeas corpus was a remedy that was available only in cases where the prisoner had been denied due process of law. This case established the principle that the federal court does not have the power to issue a writ of habeas corpus to a state prisoner.

In United States v. Singer, the Supreme Court was tasked with determining whether a patentee of a sewing machine could be sued for infringement by another party who had obtained an earlier patent on the same invention. The majority opinion held that such suits were permissible under existing law and that the defendant's prior patent did not provide any immunity from suit. Justice Field dissented, arguing that allowing two parties to sue each other over the same invention would lead to endless litigation and confusion in the courts as well as create uncertainty in inventors' rights to their inventions. He argued further that Congress should have been consulted before making such a decision since it is ultimately responsible for creating laws governing patents and copyrights. Furthermore, he believed there was no precedent or legal authority supporting this ruling which made it even more problematic than if Congress had weighed in on this issue first. Ultimately, Justice Field concluded his dissent by stating that while he agreed with much of what was said in favor of upholding the lower court’s decision, he felt compelled to express his disagreement due to its potential implications for future cases involving similar issues concerning patents and copyrights