United States v. Asher Ayres 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 Asher Ayres, who was charged with receiving stolen goods. The evidence used to convict Ayres was obtained through a search of his home without a warrant. Ayres argued that the evidence should be excluded from his trial because it was obtained illegally. The Supreme Court ruled in favor of Ayres, holding that evidence obtained through an illegal search and seizure was inadmissible in court. The Court reasoned that the Fourth Amendment of the United States Constitution protects citizens from unreasonable searches and seizures, and that the evidence obtained in this case was obtained in violation of that amendment. The Court also held that the exclusionary rule, which prohibits the use of illegally obtained evidence in court, applied in this case. This case established the precedent that evidence obtained through an illegal search and seizure is inadmissible in court. This ruling has been used in numerous cases since then to protect citizens from unreasonable searches and seizures.

In United States v. Asher Ayres, the Supreme Court was asked to decide whether a person who had been convicted of treason in a state court could be tried again for the same offense in federal court. The majority opinion held that such double jeopardy was permissible under the Constitution and that Congress had not prohibited it by statute. However, Justice Field dissented from this decision, arguing that allowing someone to be tried twice for the same crime violated both common law principles and fundamental fairness. He argued further that if Congress intended to permit double jeopardy they should have made their intent clear through legislation rather than leaving it up to judicial interpretation of constitutional provisions which did not explicitly address this issue. In conclusion, he believed there were sufficient protections against multiple prosecutions already available without having to resort to unconstitutional means like double jeopardy which would undermine public confidence in our legal system as well as individual rights guaranteed by our Constitution.