Final answer:
The Fourth Amendment to the United States Constitution requires search warrants for searches and arrests, protecting individuals against unreasonable searches and seizures and emphasizing probable cause for legal actions.
Step-by-step explanation:
The amendment that established the need for a search warrant before a person can be searched or arrested is the Fourth Amendment. This amendment is crucial in protecting the privacy and property of individuals against unreasonable searches and seizures. It requires that no search warrants shall be issued without probable cause, supported by an oath or affirmation, and that the warrant must particularly describe the place to be searched and the persons or things to be seized.
In summary, the Fourth Amendment safeguards against unlawful arrests and the invasion of privacy in one's home, emphasizing the legal necessity of a warrant and probable cause. Exceptions to this requirement include situations involving consent, exigent circumstances, or when evidence is in plain view.