In Carr v. United States, the Supreme Court of the United States was asked to decide whether a defendant could be convicted of a crime if the evidence presented at trial was obtained through an illegal search and seizure. The case involved a defendant, Carr, who was charged with receiving stolen goods. The evidence used to convict him was obtained through a search of his home without a warrant. The Supreme Court held that the evidence obtained through the illegal search and seizure was inadmissible and that the defendant could not be convicted on the basis of it. The Court reasoned that the Fourth Amendment of the United States Constitution protects citizens from unreasonable searches and seizures and that the evidence obtained through the illegal search and seizure was in violation of this amendment. The Court also noted that the exclusionary rule, which prohibits the use of illegally obtained evidence in criminal proceedings, was applicable in this case. The Court's decision in Carr v. United States established the principle that evidence obtained through an illegal search and seizure is inadmissible in criminal proceedings and that the exclusionary rule applies to such evidence. This decision has been cited in numerous subsequent cases and has become an important part of Fourth Amendment jurisprudence.

Justice Field delivered the dissenting opinion in Carr v. United States, arguing that the majority's interpretation of the law was too broad and would lead to an unwarranted expansion of federal power. He argued that Congress had not intended for criminal prosecution to be used as a tool for enforcing civil rights laws, but rather only when there is clear evidence of a crime being committed. Furthermore, he noted that while it may be true that some individuals have been denied their constitutional rights due to discrimination or prejudice, this does not necessarily mean they are guilty of any crime under federal law. Therefore, Justice Field concluded that Congress did not intend for criminal prosecutions to be used as a means of protecting civil rights and thus should not have been applied in this case.