The Supreme Court's decisions in Terry v. Ohio (1967) and Horton v. California (1990) both held that the police may, in certain cases, search individuals or seize their property without a warrant.
must never, even with reasonable cause, carry out a stop and frisk.
must always have a warrant to seize evidence, even if it is in plain view.
may never violate the Fourth Amendment protections concerning searches and seizures.