What is required for a search warrant to be valid?

A valid search warrant requires that it must be signed by an impartial judge. This is fundamental to the integrity of the legal process, ensuring that judicial oversight is applied before the government can infringe upon an individual's constitutional rights. The involvement of an unbiased judicial figure serves to protect citizens from arbitrary or unreasonable searches and seizures, as stipulated by the Fourth Amendment. Without this crucial signature, the warrant lacks legal authority and cannot be executed lawfully, thereby undermining the enforcement of the law.

The other options, while they might reflect procedures related to search warrants, do not constitute the necessary elements for validity. For example, a search warrant does not require a detailed plan for the search, nor does it need to involve multiple officers to be valid. Additionally, while search warrants must be executed within a reasonable timeframe, that timeframe is not limited to 24 hours universally, as the specifics can vary based on jurisdiction and circumstances surrounding the case. Thus, the signature of an impartial judge remains the essential component for the warrant's legitimacy.