United States v. Spiegel was a United States Supreme Court case that addressed the issue of whether a federal court had the authority to issue an injunction against a state court. The case arose when the United States sought to enjoin the state court from enforcing a judgment against the United States in a case involving the collection of taxes. The United States argued that the state court lacked jurisdiction to issue the judgment and that the federal court had the authority to enjoin the state court from enforcing the judgment. The Supreme Court held that the federal court did not have the authority to enjoin the state court from enforcing the judgment. The Court reasoned that the federal court lacked jurisdiction to interfere with the proceedings of a state court and that the state court had the exclusive authority to determine the validity of the judgment. The Court further held that the federal court could not interfere with the state court's proceedings unless the state court had acted in a manner that was contrary to the Constitution or laws of the United States. In conclusion, the Supreme Court held that the federal court did not have the authority to enjoin the state court from enforcing the judgment in United States v. Spiegel. The Court reasoned that the state court had the exclusive authority to determine the validity of the judgment and that the federal court could not interfere with the state court's proceedings unless the state court had acted in a manner that was contrary to the Constitution or laws of the United States.

In United States v. Spiegel, the Supreme Court was asked to decide whether a federal tax imposed on distilled spirits could be collected from an individual who had purchased those spirits prior to the enactment of the tax. The majority opinion held that such taxes were constitutional and enforceable against individuals who had already made purchases before they went into effect. Justice Field dissented, arguing that Congress did not have authority under Article I of the Constitution to impose this type of retroactive taxation without providing adequate compensation for it. He argued that if Congress wanted to impose such a tax, it should do so prospectively only and provide some form of compensation or relief for those affected by its retroactive application in order to make it fair and justifiable under law. Furthermore, he noted that there was no precedent in English common law or American jurisprudence which supported such an action by Congress as being within their power granted by Article I of the Constitution.