What is the role of a magistrate in issuing a search warrant?

The role of the magistrate in issuing a search warrant was discussed in Shadwick v. City of Tampa (1972) 407 U.S. 345, 350, 92 S.Ct. 2119, 2123, 32 L.Ed.2d 783:

"He must be neutral and detached, and he must be capable of determining whether probable cause exists for the requested arrest or search.... If ... detachment and capacity do conjoin, the magistrate has satisfied the Fourth Amendment's purpose." (See also People v. Chavez, supra, 27 Cal.App.3d 883, 886-887, 104 Cal.Rptr. 247.)