United States v. Watson 423 U.S. 411, 96 S. Ct. 820, 46 L. Ed.2d 598 (1976) An informant named Khoury told the postal inspector that Watson had given him stolen credit cards and would give him more. The informant's information was probably enough to get an arrest warrant, but the postal inspector chose not to bother. Instead, the postal inspector had Khoury set up a meeting with Watson. At the meeting, Khoury gave a signal that Watson had the cards on him. The postal inspectors swooped in and arrested Watson. Watson did not have any stolen credit cards on him. Watson consented to a search of his car. They found stolen credit cards in his car. He was charged with possession of stolen goods. The Trial Court convicted Watson. He appealed. Watson argued that the arrest was unconstitutional because the postal inspector did not have a warrant to arrest him. If they hadn't arrested him he wouldn't have consented to the search of his car, so all the evidence should be thrown out. Watson argued that the postal inspectors could have gotten an arrest warrant, but failed to do so. 18 U.S.C. §3061 (which authorized postal inspectors) gives them the ability to arrest someone without an arrest warrant, as long as they have probable cause. The Appellate Court reversed. The prosecutor appealed. The US Supreme Court reversed the Appellate Court and upheld the conviction. The US Supreme Court found there was nothing in prior case law to suggest that the 4th Amendment requires a warrant to make an arrest for a felony. Watson unsuccessfully argued that under the ancient common law, the police were only allowed to arrest someone if they had an arrest warrant, or if the person committed a crime in the presence of the police officer, or if there was reasonable grounds to believe that the person had committed a felony. The Court noted that within 48 hours of an arrest, the police have to present the prisoner to a judge for an arraignment to show that there was probable cause to make the arrest, at the time the arrest was made. That functions like a retroactive arrest warrant and helps to deter the police from arresting people wily-nily. See Gerstein v. Pugh (420 U.S. 103 (1975)) In a concurrence, it was argued that since the informer gave a signal, the postal inspector had probable cause to make the arrest, and therefore the arrest was legal because it fit into a recognized exception to the warrant requirement. There was no reason to toss out the entire concept that the 4th Amendment requires a warrant to arrest someone. Basically, the police need a warrant to arrest someone because an arrest is a lot like a search and seizure, it is just that the person is being seized, not their stuff. Since the police generally need a warrant under the 4th Amendment to search and seize someone's stuff, shouldn't the police also need a warrant to search and seize a person?