What is required to lawfully search a person or place under the privacy principle?

• A. A warrant is always required
• B. Reasonableness under the Fourth Amendment, typically supported by probable cause and/or consent
• C. A signed court order
• D. The officer's discretion

Answer: (B)

The key rule here is that searches must be reasonable under the Fourth Amendment. A search is lawful when it is reasonable, which is usually achieved by having probable cause and obtaining a warrant, or by obtaining valid consent from the person being searched. Probable cause means there are enough facts to reasonably believe a crime is involved, and a warrant is a judge’s authorization based on that showing. But a warrant isn’t the only path to reasonableness—voluntary consent can make a search lawful without one, and there are recognized exceptions (like exigent circumstances or searches incident to a lawful arrest) that permit searches without a warrant. So the general requirement is reasonableness under the Fourth Amendment, with probable cause and/or consent as the common ways to achieve it.