Under the Fourth Amendment, what must be shown to obtain an arrest or search warrant?

To obtain an arrest or search warrant under the Fourth Amendment, it is essential to demonstrate probable cause. Probable cause refers to a reasonable belief, based on facts and circumstances, that a crime has been committed or that evidence of a crime is present in the location to be searched. This standard protects individuals against unreasonable searches and seizures, ensuring that warrants are issued based on more than just hunches or vague suspicions.

Mere suspicion is insufficient to meet the legal standard required for warrants, as it lacks the concrete basis that probable cause requires. Similarly, while witness statements can contribute to building probable cause, they alone do not fulfill the requirement for obtaining a warrant without the underlying reasonable belief that a crime has occurred or that evidence exists. Thus, it is the concept of probable cause that fundamentally empowers law enforcement to seek legal authorization to carry out arrests or searches while respecting constitutional protections.