The defendant had argued that anticipatory warrants in general violated the Fourth Amendment's requirement that "no Warrants shall issue, but upon probable cause," because the anticipated probable cause does not exist at the time of the warrant's issuance. The Court first noted that the courts of appeals had unanimously rejected this argument. It asserted that all warrants are in a sense "anticipatory," because any search is only reasonable if there is probable cause for it when the search is conducted. "In the typical case where the police seek permission to search a house for an item they believe is already located there, the magistrate's determination that there is probable cause for the search amounts to a prediction that the item will still be there when the warrant is executed." The Court concluded that this makes anticipatory warrants no different in principle from ordinary warrants.