United States v. Wilder was a United States Supreme Court case that dealt with the issue of whether a defendant could be convicted of a crime if the evidence presented was obtained through an illegal search and seizure. The case involved a man named Wilder who was accused of stealing a horse. The police searched Wilder's house without a warrant and found evidence of the crime. Wilder argued that the evidence should not be allowed in court because it was obtained through an illegal search and seizure. The Supreme Court ruled in favor of Wilder, holding that evidence obtained through an illegal search and seizure was inadmissible in court. The Court reasoned that allowing such evidence would encourage law enforcement to violate the Fourth Amendment, which protects citizens from unreasonable searches and seizures. The Court also noted that the exclusionary rule, which prohibits the use of illegally obtained evidence in court, was necessary to protect citizens' rights and to ensure that law enforcement followed the law. The decision in United States v. Wilder established the exclusionary rule, which has since been used to protect citizens from unreasonable searches and seizures. The case also established the principle that evidence obtained through an illegal search and seizure is inadmissible in court.

In United States v. Wilder, the Supreme Court was asked to decide whether a federal statute that allowed for the sale of public lands in certain states applied to lands already owned by private individuals. The majority opinion held that it did not apply and thus could not be enforced against such land owners. However, Justice Field dissented from this decision arguing that Congress had clear authority under the Constitution to pass laws regulating commerce between different states and with foreign nations, including those relating to public lands within their borders. He argued further that if Congress intended for its law regarding public land sales in certain states to apply only when there were no prior claims on them then they should have made this explicit in the text of their legislation rather than leaving it open-ended as they did here. As such he concluded that since Congress had failed to do so then any reasonable interpretation must include pre-existing claims on these lands and thus allow for enforcement against them as well.