United States v. Britton & Another is a United States Supreme Court case that was decided in 1883. The case involved two individuals, Britton and another, who were charged with violating the Neutrality Act of 1794. The Act prohibited citizens from engaging in any activity that would aid a foreign nation in a war against the United States. The defendants were accused of providing arms and ammunition to the government of Mexico, which was then at war with the United States. The Supreme Court held that the defendants had violated the Neutrality Act and were guilty of the charges. The Court reasoned that the Act was intended to protect the United States from foreign interference and that the defendants had acted in a manner that was contrary to the spirit of the Act. The Court also noted that the defendants had acted with knowledge of the consequences of their actions and that they had acted with the intent to aid a foreign nation in a war against the United States. The Court's decision in United States v. Britton & Another established that the Neutrality Act of 1794 was a valid law and that individuals who violated it could be held accountable for their actions. The decision also established that individuals who knowingly and intentionally aid a foreign nation in a war against the United States can be held liable for their actions.

Justice Field delivered the dissenting opinion in United States v. Britton & Another, arguing that Congress did not have the power to pass a law which would allow for an individual's property to be seized without due process of law. He argued that this was a violation of the Fifth Amendment and therefore unconstitutional. He also noted that if such laws were allowed, it could lead to arbitrary seizures by government officials with no accountability or recourse for those affected. Justice Field concluded his dissent by stating that Congress should only be able to pass laws which are consistent with constitutional principles and protect citizens from unreasonable searches and seizures as guaranteed under the Fourth Amendment.