> So the Fourth Amendment removed that concept completely by directing that any unreasonable search of a person or their house, papers or effects much be done under a warrant that was specific in nature.
It prohibits unreasonable searches outright (it doesn't require a warrant for unreasonable searches), and also limits warrants to certain standards. (Implicitly, it has been held to also mean that warrants are usually necessary for a search to be reasonable, since if there were no generally-applicable warrant requirement for reasonableness, the limitation on the conditions in which warrants may be issued would be meaningless.)
It prohibits unreasonable searches outright (it doesn't require a warrant for unreasonable searches), and also limits warrants to certain standards. (Implicitly, it has been held to also mean that warrants are usually necessary for a search to be reasonable, since if there were no generally-applicable warrant requirement for reasonableness, the limitation on the conditions in which warrants may be issued would be meaningless.)