The Fourth Amendment requires that searches be based on what?

The Fourth Amendment of the United States Constitution protects individuals from unreasonable searches and seizures, emphasizing the necessity of a warrant that is supported by probable cause. This means that law enforcement must have sufficient reason, based on facts and evidence, to believe that a crime has been committed before they can search a person's property. The requirement of a warrant serves as a safeguard against arbitrary intrusions by the government into individuals' privacy.

While consent from the property owner can allow for a search without a warrant, it’s not a requirement under the Fourth Amendment. Similarly, evidence of a crime might justify action during an investigation but does not itself warrant a search without that necessary judicial backing. Lastly, a vote from Congress has no relevance in the context of individual search and seizure regulations, as this is a matter governed by the principles outlined in the Constitution and interpreted by the courts. Therefore, the requirement of a warrant supported by probable cause is paramount in protecting the rights of individuals against state overreach.