Soule v. United States was a United States Supreme Court case that addressed the issue of whether a federal court had the power 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. The Supreme Court held that the federal court did not have the power to enjoin the state court from enforcing its judgment. The Court reasoned that the federal court did not have the power to enjoin the state court because the state court was acting within its jurisdiction and the federal court was not. The Court further reasoned that the federal court could not interfere with the state court's judgment because the state court was acting within its jurisdiction and the federal court was not. The Court also noted that the federal court could not interfere with the state court's judgment because the state court was acting in accordance with the laws of the state. In conclusion, the Supreme Court held that the federal court did not have the power to enjoin the state court from enforcing its judgment. The Court reasoned that the federal court could not interfere with the state court's judgment because the state court was acting within its jurisdiction and the federal court was not.

Justice Field delivered the dissenting opinion in Soule v. United States, arguing that the majority's decision was contrary to established precedent and would have a detrimental effect on commerce. He argued that Congress had no authority to pass laws regulating interstate commerce, as it is an exclusive power of the states under the Constitution. Furthermore, he noted that if Congress were allowed to regulate such matters, then it could effectively nullify state laws by passing conflicting regulations. He also pointed out that this case involved a contract between two parties which should be respected and enforced according to its terms regardless of any federal law or regulation passed afterwards. In conclusion, Justice Field believed that allowing Congress to interfere with contracts between private citizens would lead only chaos and confusion in commercial transactions throughout the country and should not be permitted under any circumstances.